Wireless power transfer method, apparatus and system

ABSTRACT

The present disclosure relates to a wireless power transmission method, a wireless power transmission apparatus, and a wireless charging system in a wireless power transmission field, and there is provided a communication method of a wireless power receiver performing communication with a wireless power transmitter using a plurality of slots, and the communication method may include transmitting control information to the wireless power transmitter within any one of the plurality of slots, receiving an ACK signal from the wireless power transmitter in response to the control information, performing communication with the wireless power transmitter using the any one slot, and determining the position of the any one of the plurality of slots when the ACK signal is received, wherein the position of the any one slot is determined through the counting of the remaining slots existing subsequent to the any one of the plurality of slots.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the National Stage filing under 35 U.S.C. 371 ofInternational Application No. PCT/KR2015/005661, filed on Jun. 5, 2015,which claims the benefit of earlier filing date and right of priority toKorean Application No. 10-2015-0046439, filed on Apr. 1, 2015 and alsoclaims the benefit of U.S. Provisional Application No. 62/008,297, filedon Jun. 5, 2014, the contents of which are all hereby incorporated byreference herein in their entirety.

TECHNICAL FIELD

The present disclosure relates to a wireless power transfer method, awireless power transfer apparatus, and a wireless charging system in awireless power transfer field.

BACKGROUND ART

In recent years, the method of contactlessly supplying electrical energyto wireless power receivers in a wireless manner has been used insteadof the traditional method of supplying electrical energy in a wiredmanner. The wireless power receiver receiving energy in a wirelessmanner may be directly driven by the received wireless power, or abattery may be charged by using the received wireless power, thenallowing the wireless power receiver to be driven by the charged power.

For allowing smooth wireless power transfer between a wireless powertransmitter which transmits power in a wireless manner and a wirelesspower receiver which receives power in a wireless manner, thestandardization for a technology related to the wireless power transferis undergoing.

As part of the standardization for the wireless power transfertechnology, the Wireless Power Consortium (WPC) which managestechnologies for a magnetic inductive wireless power transfer haspublished a standard document “System description Wireless PowerTransfer, Volume 1, Low Power, Part 1: Interface Definition, Version1.00 Release Candidate 1 (RC1)” for interoperability in the wirelesspower transfer on Apr. 12, 2010.

On the other hand, Power Matters Alliance as another technologystandardization consortium has been established in March 2012, developeda product line of interface standards, and published a standard documentbased on an inductive coupling technology for providing inductive andresonant power.

A wireless charging method using electromagnetic induction is frequentlyencountered in our lives, for example, is utilized by beingcommercialized in electric toothbrushes, wireless coffee ports and thelike.

On the other hand, the WPC standard prescribes a method of performingcommunication between a wireless power transmitter and a wireless powerreceiver. At present, a communication scheme prescribed by the WPCstandard, as a one-to-one communication scheme, discloses a scheme inwhich communication is carried out between one wireless powertransmitter and one wireless power receiver.

Accordingly, the present disclosure provides a communication method of awireless power transmitter for performing communication with a pluralityof wireless power receivers as well as said one-to-one communicationscheme.

DISCLOSURE OF THE INVENTION

An aspect of the present disclosure is to provide a method ofdetermining from which wireless power receiver information received at awireless power transmitter is received when one wireless powertransmitter performs communication with a plurality of wireless powerreceivers.

There is provided a communication method of a wireless power receiverperforming communication with a wireless power transmitter using aplurality of slots, and the communication method may includetransmitting control information to the wireless power transmitterwithin any one of the plurality of slots, receiving an ACK signal fromthe wireless power transmitter in response to the control information,determining the position of the any one of the plurality of slots whenthe ACK signal is received, and performing communication with thewireless power transmitter using the any one slot, wherein the positionof the any one slot is determined through the counting of the remainingslots existing subsequent to the any one of the plurality of slots.

According to an embodiment, the remaining slots may be counted using async pattern linked with the plurality of slots.

According to an embodiment, the sync pattern may be a wireless powersignal transmitted from the wireless power transmitter.

According to an embodiment, the sync pattern may include a first syncpattern existing at a start position of the plurality of slots toindicate a start of the plurality of slots and a second sync patternexisting between two consecutive slots of the plurality of slots toindicate information associated with the two consecutive slots, and theposition of the any one slot may be determined by counting a number ofsecond sync patterns received at the wireless power receiver until thefirst sync pattern is received at the wireless power receiver subsequentto receiving the ACK signal.

According to an embodiment, the plurality of slots may include a syncpattern existing at a start position of the plurality of slots toindicate a start of the plurality of slots, and the remaining slots maybe counted using a time interval subsequent to a time point at which theACK signal is received and prior to a time point at which the syncpattern is received.

According to an embodiment, each slot constituting the plurality ofslots, respectively, may have the same time interval.

According to an embodiment, said performing communication with thewireless power transmitter may calculate a time interval subsequent to atime point at which the sync pattern is received and prior to a timepoint at which the any one slot is provided based on the position of theany one slot to perform communication.

According to an embodiment, the sync pattern may include informationindicating whether or not each of the plurality of slots is allocated toa wireless power receiver.

According to an embodiment, said performing communication with thewireless power transmitter may transmit the control information to thewireless power transmitter only within any one of the plurality of slotsbased on the determined position.

According to an embodiment, said performing communication with thewireless power transmitter may limit the transmission of the controlinformation to the wireless power transmitter within the remaining slotsother than the any one of the plurality of slots.

There is provided a communication method of a wireless power transmitterperforming communication with a wireless power receiver using aplurality of slots, and the communication method may include receivingspecific information from the wireless power receiver within any one ofthe plurality of slots, transmitting an ACK signal to the wireless powerreceiver in response to the specific information, allocating the any oneslot to the wireless power receiver to perform communication with thewireless power receiver, and performing communication with the wirelesspower receiver using the allocated any one slot, wherein the slotinformation of the any one slot is stored when the any one slot isallocated.

According to an embodiment, the slot information of the any one slot maybe position information of the any one slot within the plurality ofslots.

According to an embodiment, a sync pattern may be located at the mostfront side of the plurality of slots, and the position of the any oneslot may be a distance of each slot based on the position of the syncpattern.

According to an embodiment, the control information may include at leastone of the control error value information and power amount information.

According to an embodiment, said performing communication with thewireless power receiver may limit the reception of the specificinformation within the remaining slots other than the any one of theplurality of slots.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary view conceptually illustrating a wireless powertransmitter and a wireless power receiver according to the embodimentsof the present invention.

FIGS. 2A and 2B are exemplary block diagrams illustrating theconfiguration of a wireless power transmitter and a wireless powerreceiver that can be employed in the embodiments disclosed herein,respectively.

FIG. 3 is a view illustrating a concept in which power is transferredfrom a wireless power transmitter to a wireless power receiver in awireless manner according to an inductive coupling method.

FIGS. 4A and 4B are block diagrams illustrating part of the wirelesspower transmitter and wireless power receiver in a magnetic inductionmethod that can be employed in the embodiments disclosed herein.

FIG. 5 is a block diagram illustrating a wireless power transmitterconfigured to have one or more transmitting coils receiving poweraccording to an inductive coupling method that can be employed in theembodiments disclosed herein.

FIG. 6 is a view illustrating a concept in which power is transferred toa wireless power receiver from a wireless power transmitter in awireless manner according to a resonance coupling method.

FIGS. 7A and 7B are block diagrams illustrating part of the wirelesspower transmitter and wireless power receiver in a resonance method thatcan be employed in the embodiments disclosed herein.

FIG. 8 is a block diagram illustrating a wireless power transmitterconfigured to have one or more transmitting coils receiving poweraccording to a resonance coupling method that can be employed in theembodiments disclosed herein.

FIG. 9 a view illustrating a concept of transmitting and receiving apacket between a wireless power transmitter and an electronic devicethrough the modulation and demodulation of a wireless power signal intransferring power in a wireless manner disclosed herein.

FIG. 10 is a view illustrating a configuration of transmitting andreceiving a power control message in transferring power in a wirelessmanner disclosed herein.

FIGS. 11A, 11B and 11C are views illustrating forms of signals uponmodulation and demodulation executed in a wireless power transferdisclosed herein.

FIGS. 12A, 12B and 12C are views illustrating a packet including a powercontrol message used in a wireless power transfer method according tothe embodiments disclosed herein.

FIG. 13 is a view illustrating operation phases of the wireless powertransmitter and wireless power receiver according to the embodimentsdisclosed herein.

FIGS. 14 to 18 are views illustrating the structure of packets includinga power control message between the wireless power transmitter and thewireless power receiver.

FIG. 19 is a conceptual view illustrating a method of transferring powerto at least one wireless power receiver from a wireless powertransmitter.

FIGS. 20A, 20B and 20C are structural views illustrating a framestructure for performing communication according to the presentdisclosure.

FIG. 21a and FIG. 21b illustrate a sync pattern according to the presentdisclosure.

FIG. 22 illustrates the operation states of a wireless power transmitterand a wireless power receiver that perform many-to-one communication.

FIG. 23 illustrates a control information packet, and

FIG. 24 illustrates an identification data packet, and

FIG. 25 illustrates a configuration packet, and

FIG. 26 illustrates an SRQ data packet, and

FIG. 27 illustrates an EPT packet, and

FIG. 28 illustrates a charging status packet.

FIGS. 29, 30A and 30B illustrate a method of counting the position of aslot allocated to the wireless power transmitter and wireless powerreceiver in a shared mode.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The technologies disclosed herein may be applicable to wireless powertransmission (contactless power transmission). However, the technologiesdisclosed herein are not limited to this, and may be also applicable toall kinds of power transmission systems and methods, wireless chargingcircuits and methods to which the technological spirit of the technologycan be applicable, in addition to the methods and apparatuses usingpower transmitted in a wireless manner.

It should be noted that technological terms used herein are merely usedto describe a specific embodiment, but not to limit the presentinvention. Also, unless particularly defined otherwise, technologicalterms used herein should be construed as a meaning that is generallyunderstood by those having ordinary skill in the art to which theinvention pertains, and should not be construed too broadly or toonarrowly. Furthermore, if technological terms used herein are wrongterms unable to correctly express the spirit of the invention, then theyshould be replaced by technological terms that are properly understoodby those skilled in the art. In addition, general terms used in thisinvention should be construed based on the definition of dictionary, orthe context, and should not be construed too broadly or too narrowly.

Incidentally, unless clearly used otherwise, expressions in the singularnumber include a plural meaning. In this application, the terms“comprising” and “including” should not be construed to necessarilyinclude all of the elements or steps disclosed herein, and should beconstrued not to include some of the elements or steps thereof, orshould be construed to further include additional elements or steps.

In addition, a suffix “module” or “unit” used for constituent elementsdisclosed in the following description is merely intended for easydescription of the specification, and the suffix itself does not giveany special meaning or function.

Furthermore, the terms including an ordinal number such as first,second, etc. can be used to describe various elements, but the elementsshould not be limited by those terms. The terms are used merely for thepurpose to distinguish an element from the other element. For example, afirst element may be named to a second element, and similarly, a secondelement may be named to a first element without departing from the scopeof right of the invention.

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings, and thesame or similar elements are designated with the same numeral referencesregardless of the numerals in the drawings and their redundantdescription will be omitted.

In describing the present invention, moreover, the detailed descriptionwill be omitted when a specific description for publicly knowntechnologies to which the invention pertains is judged to obscure thegist of the present invention. Also, it should be noted that theaccompanying drawings are merely illustrated to easily explain thespirit of the invention, and therefore, they should not be construed tolimit the spirit of the invention by the accompanying drawings.

DEFINITION

Many-to-one communication: communicating between one transmitter (Tx)and many receivers (Rx)

Unidirectional communication: transmitting a required message only froma receiver to a transmitter

Here, the transmitter and the receiver indicate the same as atransmitting unit (device) and a receiving unit (device), respectively.Hereinafter, those terms may be used together.

Conceptual View of Wireless Power Transmitter and Wireless PowerReceiver

FIG. 1 is an exemplary view conceptually illustrating a wireless powertransmitter and a wireless power receiver according to the embodimentsof the present invention.

Referring to FIG. 1, the wireless power transmitter 100 may be a powertransfer apparatus configured to transfer power required for thewireless power receiver 200 in a wireless manner.

Furthermore, the wireless power transmitter 100 may be a wirelesscharging apparatus configured to charge a battery of the wireless powerreceiver 200 by transferring power in a wireless manner. A case wherethe wireless power transmitter 100 is a wireless charging apparatus willbe described later with reference to FIG. 9.

Additionally, the wireless power transmitter 100 may be implemented withvarious forms of apparatuses transferring power to the wireless powerreceiver 200 requiring power in a contactless state.

The wireless power receiver 200 is a device that is operable byreceiving power from the wireless power transmitter 100 in a wirelessmanner. Furthermore, the wireless power receiver 200 may charge abattery using the received wireless power.

On the other hand, an electronic device for receiving power in awireless manner as described herein should be construed broadly toinclude a portable phone, a cellular phone, a smart phone, a personaldigital assistant (PDA), a portable multimedia player (PMP), a tablet, amultimedia device, or the like, in addition to an input/output devicesuch as a keyboard, a mouse, an audio-visual auxiliary device, and thelike.

The wireless power receiver 200, as described later, may be a mobilecommunication terminal (for example, a portable phone, a cellular phone,and a tablet and the like) or a multimedia device.

On the other hand, the wireless power transmitter 100 may transfer powerin a wireless manner without mutual contact to the wireless powerreceiver 200 using one or more wireless power transfer methods. In otherwords, the wireless power transmitter 100 may transfer power using atleast one of an inductive coupling method based on magnetic inductionphenomenon by the wireless power signal and a magnetic resonancecoupling method based on electromagnetic resonance phenomenon by awireless power signal at a specific frequency.

Wireless power transfer in the inductive coupling method is a technologytransferring power in a wireless manner using a primary coil and asecondary coil, and refers to the transmission of power by inducing acurrent from a coil to another coil through a changing magnetic field bya magnetic induction phenomenon.

Wireless power transfer in the inductive coupling method refers to atechnology in which the wireless power receiver 200 generates resonanceby a wireless power signal transmitted from the wireless powertransmitter 100 to transfer power from the wireless power transmitter100 to the wireless power receiver 200 by the resonance phenomenon.

Hereinafter, the wireless power transmitter 100 and wireless powerreceiver 200 according to the embodiments disclosed herein will bedescribed in detail. In assigning reference numerals to the constituentelements in each of the following drawings, the same reference numeralswill be used for the same constituent elements even though they areshown in a different drawing.

FIGS. 2A and 2B are exemplary block diagrams illustrating theconfiguration of a wireless power transmitter 100 and a wireless powerreceiver 200 that can be employed in the embodiments disclosed herein.

Wireless Power Transmitter

Referring to FIG. 2A, the wireless power transmitter 100 may include apower transmission unit 110. The power transmission unit 110 may includea power conversion unit 111 and a power transmission control unit 112.

The power conversion unit 111 transfers power supplied from atransmission side power supply unit 190 to the wireless power receiver200 by converting it into a wireless power signal. The wireless powersignal transferred by the power conversion unit 111 is generated in theform of a magnetic field or electro-magnetic field having an oscillationcharacteristic. For this purpose, the power conversion unit 111 may beconfigured to include a coil for generating the wireless power signal.

The power conversion unit 111 may include a constituent element forgenerating a different type of wireless power signal according to eachpower transfer method. For example, the power conversion unit 111 mayinclude a primary coil for forming a changing magnetic field to induce acurrent to a secondary coil of the wireless power receiver 200.Furthermore, the power conversion unit 111 may include a coil (orantenna) for forming a magnetic field having a specific resonantfrequency to generate a resonant frequency in the wireless powerreceiver 200 according to the resonance coupling method.

Furthermore, the power conversion unit 111 may transfer power using atleast one of the foregoing inductive coupling method and the resonancecoupling method.

Among the constituent elements included in the power conversion unit111, those for the inductive coupling method will be described laterwith reference to FIGS. 4 and 5, and those for the resonance couplingmethod will be described with reference to FIGS. 7 and 8.

On the other hand, the power conversion unit 111 may further include acircuit for controlling the characteristics of a used frequency, anapplied voltage, an applied current or the like to form the wirelesspower signal.

The power transmission control unit 112 controls each of the constituentelements included in the power transmission unit 110 The powertransmission control unit 112 may be implemented to be integrated intoanother control unit (not shown) for controlling the wireless powertransmitter 100.

On the other hand, a region to which the wireless power signal can beapproached may be divided into two types. First, an active area denotesa region through which a wireless power signal transferring power to thewireless power receiver 200 is passed. Next, a semi-active area denotesan interest region in which the wireless power transmitter 100 candetect the existence of the wireless power receiver 200. Here, the powertransmission control unit 112 may detect whether the wireless powerreceiver 200 is placed in the active area or detection area or removedfrom the area. Specifically, the power transmission control unit 112 maydetect whether or not the wireless power receiver 200 is placed in theactive area or detection area using a wireless power signal formed fromthe power conversion unit 111 or a sensor separately provided therein.For instance, the power transmission control unit 112 may detect thepresence of the wireless power receiver 200 by monitoring whether or notthe characteristic of power for forming the wireless power signal ischanged by the wireless power signal, which is affected by the wirelesspower receiver 200 existing in the detection area. However, the activearea and detection area may vary according to the wireless powertransfer method such as an inductive coupling method, a resonancecoupling method, and the like.

The power transmission control unit 112 may perform the process ofidentifying the wireless power receiver 200 or determine whether tostart wireless power transfer according to a result of detecting theexistence of the wireless power receiver 200.

Furthermore, the power transmission control unit 112 may determine atleast one characteristic of a frequency, a voltage, and a current of thepower conversion unit 111 for forming the wireless power signal. Thedetermination of the characteristic may be carried out by a condition atthe side of the wireless power transmitter 100 or a condition at theside of the wireless power receiver 200.

The power transmission control unit 112 may receive a power controlmessage from the wireless power receiver 200. The power transmissioncontrol unit 112 may determine at least one characteristic of afrequency, a voltage and a current of the power conversion unit 111based on the received power control message, and additionally performother control operations based on the power control message.

For example, the power transmission control unit 112 may determine atleast one characteristic of a frequency, a voltage and a current used toform the wireless power signal according to the power control messageincluding at least one of rectified power amount information, chargingstate information and identification information in the wireless powerreceiver 200.

Furthermore, as another control operation using the power controlmessage, the wireless power transmitter 100 may perform a typicalcontrol operation associated with wireless power transfer based on thepower control message. For example, the wireless power transmitter 100may receive information associated with the wireless power receiver 200to be auditorily or visually outputted through the power controlmessage, or receive information required for authentication betweendevices.

In exemplary embodiments, the power transmission control unit 112 mayreceive the power control message through the wireless power signal. Inother exemplary embodiment, the power transmission control unit 112 mayreceive the power control message through a method for receiving userdata.

In order to receive the foregoing power control message, the wirelesspower transmitter 100 may further include a modulation/demodulation unit113 electrically connected to the power conversion unit 111. Themodulation/demodulation unit 113 may modulate a wireless power signalthat has been modulated by the wireless power receiver 200 and use it toreceive the power control message.

In addition, the power transmission control unit 112 may acquire a powercontrol message by receiving user data including a power control messageby a communication means (not shown) included in the wireless powertransmitter 100.

[For Supporting In-Band Two-Way Communication]

Under a wireless power transfer environment allowing for bi-directionalcommunications according to the exemplary embodiments disclosed herein,the power transmission control unit 112 may transmit data to thewireless power receiver 200. The data transmitted by the powertransmission control unit 112 may be transmitted to request the wirelesspower receiver 200 to send the power control message.

Wireless Power Receiver

Referring to FIG. 2B, the wireless power receiver 200 may include apower supply unit 290. The power supply unit 290 supplies power requiredfor the operation of the wireless power receiver 200. The power supplyunit 290 may include a power receiving unit 291 and a power receptioncontrol unit 292.

The power receiving unit 291 receives power transferred from thewireless power transmitter 100 in a wireless manner.

The power receiving unit 291 may include constituent elements requiredto receive the wireless power signal according to a wireless powertransfer method. Furthermore, the power receiving unit 291 may receivepower according to at least one wireless power transfer method, and inthis case, the power receiving unit 291 may include constituent elementsrequired for each method.

First, the power receiving unit 291 may include a coil for receiving awireless power signal transferred in the form of a magnetic field orelectromagnetic field having a vibration characteristic.

For instance, as a constituent element according to the inductivecoupling method, the power receiving unit 291 may include a secondarycoil to which a current is induced by a changing magnetic field. Inexemplary embodiments, the power receiving unit 291, as a constituentelement according to the resonance coupling method, may include a coiland a resonant circuit in which resonance phenomenon is generated by amagnetic field having a specific resonant frequency.

In another exemplary embodiments, when the power receiving unit 291receives power according to at least one wireless power transfer method,the power receiving unit 291 may be implemented to receive power byusing a coil, or implemented to receive power by using a coil formeddifferently according to each power transfer method.

Among the constituent elements included in the power receiving unit 291,those for the inductive coupling method will be described later withreference to FIG. 4, and those for the resonance coupling method withreference to FIG. 7.

On the other hand, the power receiving unit 291 may further include arectifier and a regulator to convert the wireless power signal into adirect current. Furthermore, the power receiving unit 291 may furtherinclude a circuit for protecting an overvoltage or overcurrent frombeing generated by the received power signal.

The power reception control unit 292 may control each constituentelement included in the power supply unit 290.

Specifically, the power reception control unit 292 may transfer a powercontrol message to the wireless power transmitter 100. The power controlmessage may instruct the wireless power transmitter 100 to initiate orterminate a transfer of the wireless power signal. Furthermore, thepower control message may instruct the wireless power transmitter 100 tocontrol a characteristic of the wireless power signal.

In exemplary embodiments, the power reception control unit 292 maytransmit the power control message through at least one of the wirelesspower signal and user data.

In order to transmit the foregoing power control message, the wirelesspower receiver 200 may further include a modulation/demodulation unit293 electrically connected to the power receiving unit 291. Themodulation/demodulation unit 293, similarly to the case of the wirelesspower transmitter 100, may be used to transmit the power control messagethrough the wireless power signal. The power communicationsmodulation/demodulation unit 293 may be used as a means for controllinga current and/or voltage flowing through the power conversion unit 111of the wireless power transmitter 100. Hereinafter, a method forallowing the power communications modulation/demodulation unit 113 or293 at the side of the wireless power transmitter 100 and at the side ofthe wireless power receiver 200, respectively, to be used to transmitand receive a power control message through a wireless power signal willbe described.

A wireless power signal formed by the power conversion unit 111 isreceived by the power receiving unit 291. At this time, the powerreception control unit 292 controls the power communicationsmodulation/demodulation unit 293 at the side of the wireless powerreceiver 200 to modulate the wireless power signal. For instance, thepower reception control unit 292 may perform a modulation process suchthat a power amount received from the wireless power signal is varied bychanging a reactance of the power communications modulation/demodulationunit 293 connected to the power receiving unit 291. The change of apower amount received from the wireless power signal results in thechange of a current and/or voltage of the power conversion unit 111 forforming the wireless power signal. At this time, themodulation/demodulation unit 113 at the side of the wireless powertransmitter 100 may detect a change of the current and/or voltage toperform a demodulation process.

In other words, the power reception control unit 292 may generate apacket including a power control message intended to be transferred tothe wireless power transmitter 100 and modulate the wireless powersignal to allow the packet to be included therein, and the powertransmission control unit 112 may decode the packet based on a result ofperforming the demodulation process of the power communicationsmodulation/demodulation unit 113 to acquire the power control messageincluded in the packet.

In addition, the power reception control unit 292 may transmit a powercontrol message to the wireless power transmitter 100 by transmittinguser data including the power control message by a communication means(not shown) included in the wireless power receiver 200.

[For Supporting In-Band Two-Way Communication]

Under a wireless power transfer environment allowing for bi-directionalcommunications according to the exemplary embodiments disclosed herein,the power reception control unit 292 may receive data to the wirelesspower transmitter 100. The data transmitted by the wireless powertransmitter 100 may be transmitted to request the wireless powerreceiver 200 to send the power control message.

In addition, the power supply unit 290 may further include a charger 298and a battery 299.

The wireless power receiver 200 receiving power for operation from thepower supply unit 290 may be operated by power transferred from thewireless power transmitter 100, or operated by charging the battery 299using the transferred power and then receiving the charged power. Atthis time, the power reception control unit 292 may control the charger298 to perform charging using the transferred power.

Hereinafter, description will be given of a wireless power transmitterand a wireless power receiver applicable to the exemplary embodimentsdisclosed herein. First, a method of allowing the wireless powertransmitter to transfer power to the electronic device according to theinductive coupling method will be described with reference to FIGS. 3through 5.

Inductive Coupling Method

FIG. 3 is a view illustrating a concept in which power is transferredfrom a wireless power transmitter to an electronic device in a wirelessmanner according to an inductive coupling method.

When the power of the wireless power transmitter 100 is transferred inan inductive coupling method, if the strength of a current flowingthrough a primary coil within the power transmission unit 110 ischanged, then a magnetic field passing through the primary coil will bechanged by the current. The changed magnetic field generates an inducedelectromotive force at a secondary coil in the wireless power receiver200.

According to the foregoing method, the power conversion unit 111 of thewireless power transmitter 100 may include a transmitting (Tx) coil 1111a being operated as a primary coil in magnetic induction. Furthermore,the power receiving unit 291 of the wireless power receiver 200 mayinclude a receiving (Rx) coil 2911 a being operated as a secondary coilin magnetic induction.

First, the wireless power transmitter 100 and wireless power receiver200 are disposed in such a manner that the transmitting coil 1111 a atthe side of the wireless power transmitter 100 and the receiving coil atthe side of the wireless power receiver 200 are located adjacent to eachother. Then, if the power transmission control unit 112 controls acurrent of the transmitting coil (Tx coil) 1111 a to be changed, thenthe power receiving unit 291 controls power to be supplied to thewireless power receiver 200 using an electromotive force induced to thereceiving coil (Rx coil) 2911 a.

The efficiency of wireless power transfer by the inductive couplingmethod may be little affected by a frequency characteristic, butaffected by an alignment and distance between the wireless powertransmitter 100 and the wireless power receiver 200 including each coil.

On the other hand, in order to perform wireless power transfer in theinductive coupling method, the wireless power transmitter 100 may beconfigured to include an interface surface (not shown) in the form of aflat surface. One or more electronic devices may be placed at an upperportion of the interface surface, and the transmitting coil 1111 a maybe mounted at a lower portion of the interface surface. In this case, avertical spacing is formed in a small-scale between the transmittingcoil 1111 a mounted at a lower portion of the interface surface and thereceiving coil 2911 a of the wireless power receiver 200 placed at anupper portion of the interface surface, and thus a distance between thecoils becomes sufficiently small to efficiently implement contactlesspower transfer by the inductive coupling method.

Furthermore, an alignment indicator (not shown) indicating a locationwhere the wireless power receiver 200 is to be placed at an upperportion of the interface surface. The alignment indicator indicates alocation of the wireless power receiver 200 where an alignment betweenthe transmitting coil 1111 a mounted at a lower portion of the interfacesurface and the receiving coil 2911 a can be suitably implemented. Thealignment indicator may alternatively be simple marks, or may be formedin the form of a protrusion structure for guiding the location of thewireless power receiver 200. Otherwise, the alignment indicator may beformed in the form of a magnetic body such as a magnet mounted at alower portion of the interface surface, thereby guiding the coils to besuitably arranged by mutual magnetism to a magnetic body having anopposite polarity mounted within the wireless power receiver 200.

On the other hand, the wireless power transmitter 100 may be formed toinclude one or more transmitting coils. The wireless power transmitter100 may selectively use some of coils suitably arranged with thereceiving coil 2911 a of the wireless power receiver 200 among the oneor more transmitting coils to enhance the power transmission efficiency.The wireless power transmitter 100 including the one or moretransmitting coils will be described later with reference to FIG. 5.

Hereinafter, configurations of the wireless power transmitter andelectronic device using an inductive coupling method applicable to theembodiments disclosed herein will be described in detail.

Wireless Power Transmitter and Electronic Device in Inductive CouplingMethod

FIG. 4 is a block diagram illustrating part of the wireless powertransmitter 100 and wireless power receiver 200 in a magnetic inductionmethod that can be employed in the embodiments disclosed herein. Aconfiguration of the power transmission unit 110 included in thewireless power transmitter 100 will be described with reference to FIG.4A, and a configuration of the power supply unit 290 included in thewireless power receiver 200 will be described with reference to FIG. 4B.

Referring to FIG. 4A, the power conversion unit 111 of the wirelesspower transmitter 100 may include a transmitting (Tx) coil 1111 a and aninverter 1112.

The transmitting coil 1111 a may form a magnetic field corresponding tothe wireless power signal according to a change of current as describedabove. The transmitting coil 1111 a may alternatively be implementedwith a planar spiral type or cylindrical solenoid type.

The inverter 1112 transforms a DC input obtained from the power supplyunit 190 into an AC waveform. The AC current transformed by the inverter1112 drives a resonant circuit including the transmitting coil 1111 aand a capacitor (not shown) to form a magnetic field in the transmittingcoil 1111 a.

In addition, the power conversion unit 111 may further include apositioning unit 1114.

The positioning unit 1114 may move or rotate the transmitting coil 1111a to enhance the effectiveness of contactless power transfer using theinductive coupling method. As described above, it is because analignment and distance between the wireless power transmitter 100 andthe wireless power receiver 200 including a primary coil and a secondarycoil may affect power transfer using the inductive coupling method. Inparticular, the positioning unit 1114 may be used when the wirelesspower receiver 200 does not exist within an active area of the wirelesspower transmitter 100.

Accordingly, the positioning unit 1114 may include a drive unit (notshown) for moving the transmitting coil 1111 a such that acenter-to-center distance of the transmitting coil 1111 a of thewireless power transmitter 100 and the receiving coil 2911 a of thewireless power receiver 200 is within a predetermined range, or rotatingthe transmitting coil 1111 a such that the centers of the transmittingcoil 1111 a and the receiving coil 2911 a are overlapped with eachother.

For this purpose, the wireless power transmitter 100 may further includea detection unit (not shown) made of a sensor for detecting the locationof the wireless power receiver 200, and the power transmission controlunit 112 may control the positioning unit 1114 based on the locationinformation of the wireless power receiver 200 received from thelocation detection sensor.

Furthermore, to this end, the power transmission control unit 112 mayreceive control information on an alignment or distance to the wirelesspower receiver 200 through the power communicationsmodulation/demodulation unit 113, and control the positioning unit 1114based on the received control information on the alignment or distance.

If the power conversion unit 111 is configured to include a plurality oftransmitting coils, then the positioning unit 1114 may determine whichone of the plurality of transmitting coils is to be used for powertransmission. The configuration of the wireless power transmitter 100including the plurality of transmitting coils will be described laterwith reference to FIG. 5.

On the other hand, the power conversion unit 111 may further include apower sensing unit 1115. The power sensing unit 1115 at the side of thewireless power transmitter 100 monitors a current or voltage flowinginto the transmitting coil 1111 a. The power sensing unit 1115 isprovided to check whether or not the wireless power transmitter 100 isnormally operated, and thus the power sensing unit 1115 may detect avoltage or current of the power supplied from the outside, and checkwhether the detected voltage or current exceeds a threshold value. Thepower sensing unit 1115, although not shown, may include a resistor fordetecting a voltage or current of the power supplied from the outsideand a comparator for comparing a voltage value or current value of thedetected power with a threshold value to output the comparison result.Based on the check result of the power sensing unit 1115, the powertransmission control unit 112 may control a switching unit (not shown)to cut off power applied to the transmitting coil 1111 a.

Referring to FIG. 4B, the power supply unit 290 of the wireless powerreceiver 200 may include a receiving (Rx) coil 2911 a and a rectifier2913.

A current is induced into the receiving coil 2911 a by a change of themagnetic field formed in the transmitting coil 1111 a. Theimplementation type of the receiving coil 2911 a may be a planar spiraltype or cylindrical solenoid type similarly to the transmitting coil1111 a.

Furthermore, series and parallel capacitors may be configured to beconnected to the receiving coil 2911 a to enhance the effectiveness ofwireless power reception or perform resonant detection.

The receiving coil 2911 a may be in the form of a single coil or aplurality of coils.

The rectifier 2913 performs a full-wave rectification to a current toconvert alternating current into direct current. The rectifier 2913, forinstance, may be implemented with a full-bridge rectifier made of fourdiodes or a circuit using active components.

In addition, the rectifier 2913 may further include a regulator forconverting a rectified current into a more flat and stable directcurrent. Furthermore, the output power of the rectifier 2913 is suppliedto each constituent element of the power supply unit 290. Furthermore,the rectifier 2913 may further include a DC-DC converter for convertingoutput DC power into a suitable voltage to adjust it to the powerrequired for each constituent element (for instance, a circuit such as acharger 298).

The power communications modulation/demodulation unit 293 may beconnected to the power receiving unit 291, and may be configured with aresistive element in which resistance varies with respect to directcurrent, and may be configured with a capacitive element in whichreactance varies with respect to alternating current. The powerreception control unit 292 may change the resistance or reactance of thepower communications modulation/demodulation unit 293 to modulate awireless power signal received to the power receiving unit 291.

On the other hand, the power supply unit 290 may further include a powersensing unit 2914. The power sensing unit 2914 at the side of thewireless power receiver 200 monitors a voltage and/or current of thepower rectified by the rectifier 2913, and if the voltage and/or currentof the rectified power exceeds a threshold value as a result ofmonitoring, then the power reception control unit 292 transmits a powercontrol message to the wireless power transmitter 100 to transfersuitable power.

Wireless Power Transmitter Configured to Include One or MoreTransmitting Coils

FIG. 5 is a block diagram illustrating a wireless power transmitterconfigured to have one or more transmission coils receiving poweraccording to an inductive coupling method that can be employed in theembodiments disclosed herein.

Referring to FIG. 5, the power conversion unit 111 of the wireless powertransmitter 100 according to the embodiments disclosed herein mayinclude one or more transmitting coils 1111 a-1 to 1111 a-n. The one ormore transmitting coils 1111 a-1 to 1111 a-n may be an array of partlyoverlapping primary coils. An active area may be determined by some ofthe one or more transmitting coils.

The one or more transmitting coils 1111 a-1 to 1111 a-n may be mountedat a lower portion of the interface surface. Furthermore, the powerconversion unit 111 may further include a multiplexer 1113 forestablishing and releasing the connection of some of the one or moretransmitting coils 1111 a-1 to 1111 a-n.

Upon detecting the location of the wireless power receiver 200 placed atan upper portion of the interface surface, the power transmissioncontrol unit 112 may take the detected location of the wireless powerreceiver 200 into consideration to control the multiplexer 1113, therebyallowing coils that can be placed in an inductive coupling relation tothe receiving coil 2911 a of the wireless power receiver 200 among theone or more transmitting coils 1111 a-1 to 1111 a-n to be connected toone another.

For this purpose, the power transmission control unit 112 may acquirethe location information of the wireless power receiver 200. Forexample, the power transmission control unit 112 may acquire thelocation of the wireless power receiver 200 on the interface surface bythe location detection unit (not shown) provided in the wireless powertransmitter 100. For another example, the power transmission controlunit 112 may alternatively receive a power control message indicating astrength of the wireless power signal from an object on the interfacesurface or a power control message indicating the identificationinformation of the object using the one or more transmitting coils 1111a-1 to 1111 a-n, respectively, and determines whether it is locatedadjacent to which one of the one or more transmitting coils based on thereceived result, thereby acquiring the location information of thewireless power receiver 200.

On the other hand, the active area as part of the interface surface maydenote a portion through which a magnetic field with a high efficiencycan pass when the wireless power transmitter 100 transfers power to thewireless power receiver 200 in a wireless manner. At this time, a singletransmitting coil or one or a combination of more transmitting coilsforming a magnetic field passing through the active area may bedesignated as a primary cell. Accordingly, the power transmissioncontrol unit 112 may determine an active area based on the detectedlocation of the wireless power receiver 200, and establish theconnection of a primary cell corresponding to the active area to controlthe multiplexer 1113, thereby allowing the receiving coil 2911 a of thewireless power receiver 200 and the coils belonging to the primary cellto be placed in an inductive coupling relation.

Furthermore, the power conversion unit 111 may further include animpedance matching unit (not shown) for controlling an impedance to forma resonant circuit with the coils connected thereto.

Hereinafter, a method for allowing a wireless power transmitter totransfer power according to a resonance coupling method will bedisclosed with reference to FIGS. 6 through 8.

Resonance Coupling Method

FIG. 6 is a view illustrating a concept in which power is transferred toan electronic device from a wireless power transmitter in a wirelessmanner according to a resonance coupling method.

First, resonance will be described in brief as follows. Resonance refersto a phenomenon in which amplitude of vibration is remarkably increasedwhen periodically receiving an external force having the same frequencyas the natural frequency of a vibration system. Resonance is aphenomenon occurring at all kinds of vibrations such as mechanicalvibration, electric vibration, and the like. Generally, when exerting avibratory force to a vibration system from the outside, if the naturalfrequency thereof is the same as a frequency of the externally appliedforce, then the vibration becomes strong, thus increasing the width.

With the same principle, when a plurality of vibrating bodies separatedfrom one another within a predetermined distance vibrate at the samefrequency, the plurality of vibrating bodies resonate with one another,and in this case, resulting in a reduced resistance between theplurality of vibrating bodies. In an electrical circuit, a resonantcircuit can be made by using an inductor and a capacitor.

When the wireless power transmitter 100 transfers power according to theinductive coupling method, a magnetic field having a specific vibrationfrequency is formed by alternating current power in the powertransmission unit 110. If a resonance phenomenon occurs in the wirelesspower receiver 200 by the formed magnetic field, then power is generatedby the resonance phenomenon in the wireless power receiver 200.

The resonant frequency may be determined by the following formula inEquation 1.

$\begin{matrix}{f = \frac{1}{2\pi \sqrt{LC}}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

Here, the resonant frequency (f) is determined by an inductance (L) anda capacitance (C) in a circuit. In a circuit forming a magnetic fieldusing a coil, the inductance can be determined by a number of turns ofthe coil, and the like, and the capacitance can be determined by a gapbetween the coils, an area, and the like. In addition to the coil, acapacitive resonant circuit may be configured to be connected thereto todetermine the resonant frequency.

Referring to FIG. 6, when power is transmitted in a wireless manneraccording to the resonance coupling method, the power conversion unit111 of the wireless power transmitter 100 may include a transmitting(Tx) coil 1111 b in which a magnetic field is formed and a resonantcircuit 1116 connected to the transmitting coil 1111 b to determine aspecific vibration frequency. The resonant circuit 1116 may beimplemented by using a capacitive circuit (capacitors), and the specificvibration frequency may be determined based on an inductance of thetransmitting coil 1111 b and a capacitance of the resonant circuit 1116.

The configuration of a circuit element of the resonant circuit 1116 maybe implemented in various forms such that the power conversion unit 111forms a magnetic field, and is not limited to a form of being connectedin parallel to the transmitting coil 1111 b as illustrated in FIG. 6.

Furthermore, the power receiving unit 291 of the wireless power receiver200 may include a resonant circuit 2912 and a receiving (Rx) coil 2911 bto generate a resonance phenomenon by a magnetic field formed in thewireless power transmitter 100. In other words, the resonant circuit2912 may be also implemented by using a capacitive circuit, and theresonant circuit 2912 is configured such that a resonant frequencydetermined based on an inductance of the receiving coil 2911 b and acapacitance of the resonant circuit 2912 has the same frequency as aresonant frequency of the formed magnetic field.

The configuration of a circuit element of the resonant circuit 2912 maybe implemented in various forms such that the power receiving unit 291generates resonance by a magnetic field, and is not limited to a form ofbeing connected in series to the receiving coil 2911 b as illustrated inFIG. 6.

The specific vibration frequency in the wireless power transmitter 100may have L_(TX), C_(TX), and may be acquired by using the Equation 1.Here, the wireless power receiver 200 generates resonance when a resultof substituting the L_(RX) and C_(RX) of the wireless power receiver 200to the Equation 1 is same as the specific vibration frequency.

According to a contactless power transfer method by resonance coupling,when the wireless power transmitter 100 and wireless power receiver 200resonate at the same frequency, respectively, an electromagnetic wave ispropagated through a short-range magnetic field, and thus there existsno energy transfer between the devices if they have differentfrequencies.

As a result, an efficiency of contactless power transfer by theresonance coupling method is greatly affected by a frequencycharacteristic, whereas the effect of an alignment and distance betweenthe wireless power transmitter 100 and the wireless power receiver 200including each coil is relatively smaller than the inductive couplingmethod.

Hereinafter, the configuration of a wireless power transmitter and anelectronic device in the resonance coupling method applicable to theembodiments disclosed herein will be described in detail.

Wireless Power Transmitter in Resonance Coupling Method

FIG. 7 is a block diagram illustrating part of the wireless powertransmitter 100 and wireless power receiver 200 in a resonance methodthat can be employed in the embodiments disclosed herein.

A configuration of the power transmission unit 110 included in thewireless power transmitter 100 will be described with reference to FIG.7A.

The power conversion unit 111 of the wireless power transmitter 100 mayinclude a transmitting (Tx) coil 1111 b, an inverter 1112, and aresonant circuit 1116. The inverter 1112 may be configured to beconnected to the transmitting coil 1111 b and the resonant circuit 1116.

The transmitting coil 1111 b may be mounted separately from thetransmitting coil 1111 a for transferring power according to theinductive coupling method, but may transfer power in the inductivecoupling method and resonance coupling method using one single coil.

The transmitting coil 1111 b, as described above, forms a magnetic fieldfor transferring power. The transmitting coil 1111 b and the resonantcircuit 1116 generate resonance when alternating current power isapplied thereto, and at this time, a vibration frequency may bedetermined based on an inductance of the transmitting coil 1111 b and acapacitance of the resonant circuit 1116.

For this purpose, the inverter 1112 transforms a DC input obtained fromthe power supply unit 190 into an AC waveform, and the transformed ACcurrent is applied to the transmitting coil 1111 b and the resonantcircuit 1116.

In addition, the power conversion unit 111 may further include afrequency adjustment unit 1117 for changing a resonant frequency of thepower conversion unit 111. The resonant frequency of the powerconversion unit 111 is determined based on an inductance and/orcapacitance within a circuit constituting the power conversion unit 111by Equation 1, and thus the power transmission control unit 112 maydetermine the resonant frequency of the power conversion unit 111 bycontrolling the frequency adjustment unit 1117 to change the inductanceand/or capacitance.

The frequency adjustment unit 1117, for example, may be configured toinclude a motor for adjusting a distance between capacitors included inthe resonant circuit 1116 to change a capacitance, or include a motorfor adjusting a number of turns or diameter of the transmitting coil1111 b to change an inductance, or include active elements fordetermining the capacitance and/or inductance

On the other hand, the power conversion unit 111 may further include apower sensing unit 1115. The operation of the power sensing unit 1115 isthe same as the foregoing description.

Referring to FIG. 7B, a configuration of the power supply unit 290included in the wireless power receiver 200 will be described. The powersupply unit 290, as described above, may include the receiving (Rx) coil2911 b and resonant circuit 2912.

In addition, the power receiving unit 291 of the power supply unit 290may further include a rectifier 2913 for converting an AC currentgenerated by resonance phenomenon into DC. The rectifier 2913 may beconfigured similarly to the foregoing description.

Furthermore, the power receiving unit 291 may further include a powersensing unit 2914 for monitoring a voltage and/or current of therectified power. The power sensing unit 2914 may be configured similarlyto the foregoing description.

Wireless Power Transmitter Configured to Include One or MoreTransmitting Coils

FIG. 8 is a block diagram illustrating a wireless power transmitterconfigured to have one or more transmission coils receiving poweraccording to a resonance coupling method that can be employed in theembodiments disclosed herein.

Referring to FIG. 8, the power conversion unit 111 of the wireless powertransmitter 100 according to the embodiments disclosed herein mayinclude one or more transmitting coils 1111 b-1 to 1111 b-n and resonantcircuits (1116-1 to 1116-n) connected to each transmitting coils.Furthermore, the power conversion unit 111 may further include amultiplexer 1113 for establishing and releasing the connection of someof the one or more transmitting coils 1111 b-1 to 1111 b-n.

The one or more transmitting coils 1111 b-1 to 1111 b-n may beconfigured to have the same vibration frequency, or some of them may beconfigured to have different vibration frequencies. It is determined byan inductance and/or capacitance of the resonant circuits (1116-1 to1116-n) connected to the one or more transmitting coils 1111 b-1 to 1111b-n, respectively.

For this purpose, the frequency adjustment unit 1117 may be configuredto change an inductance and/or capacitance of the resonant circuits(1116-1 to 1116-n) connected to the one or more transmitting coils 1111b-1 to 1111 b-n, respectively.

In-Band Communication

FIG. 9 a view illustrating the concept of transmitting and receiving apacket between a wireless power transmitter and a wireless powerreceiver through the modulation and demodulation of a wireless powersignal in transferring power in a wireless manner disclosed herein.

As illustrated in FIG. 9, the power conversion unit 111 included in thewireless power transmitter 100 may generate a wireless power signal. Thewireless power signal may be generated through the transmitting coil1111 included in the power conversion unit 111.

The wireless power signal 10 a generated by the power conversion unit111 may arrive at the wireless power receiver 200 so as to be receivedthrough the power receiving unit 291 of the wireless power receiver 200.The generated wireless power signal may be received through thereceiving coil 2911 included in the power receiving unit 291.

The power reception control unit 292 may control themodulation/demodulation unit 293 connected to the power receiving unit291 to modulate the wireless power signal while the wireless powerreceiver 200 receives the wireless power signal. When the receivedwireless power signal is modulated, the wireless power signal may form aclosed-loop within a magnetic field or an electro-magnetic field. Thismay allow the wireless power transmitter 100 to sense a modulatedwireless power signal 10 b. The modulation/demodulation unit 113 maydemodulate the sensed wireless power signal and decode the packet fromthe demodulated wireless power signal.

The modulation method employed for the communication between thewireless power transmitter 100 and the wireless power receiver 200 maybe an amplitude modulation. As aforementioned, the amplitude modulationis a backscatter modulation may be a backscatter modulation method inwhich the power communications modulation/demodulation unit 293 at theside of the wireless power receiver 200 changes an amplitude of thewireless power signal 10 a formed by the power conversion unit 111 andthe power reception control unit 292 at the side of the wireless powertransmitter 100 detects an amplitude of the modulated wireless powersignal 10 b.

Modulation and Demodulation of Wireless Power Signal

Hereinafter, description will be given of modulation and demodulation ofa packet, which is transmitted or received between the wireless powertransmitter 100 and the wireless power receiver 200 with reference toFIGS. 10 and 11.

FIG. 10 is a view illustrating a configuration of transmitting orreceiving a power control message in transferring power in a wirelessmanner disclosed herein, and FIG. 11 is a view illustrating forms ofsignals upon modulation and demodulation executed in the wireless powertransfer disclosed herein.

Referring to FIG. 10, the wireless power signal received through thepower receiving unit 291 of the wireless power receiver 200, asillustrated in FIG. 11A, may be a non-modulated wireless power signal51. The wireless power receiver 200 and the wireless power transmitter100 may establish a resonance coupling according to a resonantfrequency, which is set by the resonant circuit 2912 within the powerreceiving unit 291, and the wireless power signal 51 may be receivedthrough the receiving coil 2911 b.

The power reception control unit 292 may modulate the wireless powersignal 51 received through the power receiving unit 291 by changing aload impedance within the modulation/demodulation unit 293. Themodulation/demodulation unit 293 may include a passive element 2931 andan active element 2932 for modulating the wireless power signal 51. Themodulation/demodulation unit 293 may modulate the wireless power signal51 to include a packet, which is desired to be transmitted to thewireless power transmitter 100. Here, the packet may be input into theactive element 2932 within the modulation/demodulation unit 293.

Afterwards, the power transmission control unit 112 of the wirelesspower transmitter 100 may demodulate a modulated wireless power signal52 through an envelop detection, and decode the detected signal 53 intodigital data 54. The demodulation may detect a current or voltageflowing into the power conversion unit 111 to be classified into twostates, a HI phase and a LO phase, and acquire a packet to betransmitted by the wireless power receiver 200 based on digital dataclassified according to the states.

Hereinafter, a process of allowing the wireless power transmitter 100 toacquire a power control message to be transmitted by the wireless powerreceiver 200 from the demodulated digital data will be described.

Referring to FIG. 11B, the power transmission control unit 112 detectsan encoded bit using a clock signal (CLK) from an envelope detectedsignal. The detected encoded bit is encoded according to a bit encodingmethod used in the modulation process at the side of the wireless powerreceiver 200. The bit encoding method may correspond to any one ofnon-return to zero (NRZ) and bi-phase encoding.

For instance, the detected bit may be a differential bi-phase (DBP)encoded bit. According to the DBP encoding, the power reception controlunit 292 at the side of the wireless power receiver 200 is allowed tohave two state transitions to encode data bit 1, and to have one statetransition to encode data bit 0. In other words, data bit 1 may beencoded in such a manner that a transition between the HI state and LOstate is generated at a rising edge and falling edge of the clocksignal, and data bit 0 may be encoded in such a manner that a transitionbetween the HI state and LO state is generated at a rising edge of theclock signal.

On the other hand, the power transmission control unit 112 may acquiredata in a byte unit using a byte format constituting a packet from a bitstring detected according to the bit encoding method. For instance, thedetected bit string may be transferred by using an 11-bit asynchronousserial format as illustrated in FIG. 12C. In other words, the detectedbit may include a start bit indicating the beginning of a byte and astop bit indicating the end of a byte, and also include data bits (b0 tob7) between the start bit and the stop bit. Furthermore, it may furtherinclude a parity bit for checking an error of data. The data in a byteunit constitutes a packet including a power control message.

[For Supporting In-Band Two-Way Communication]

As aforementioned, FIG. 9 has illustrated that the wireless powerreceiver 200 transmits a packet using a carrier signal 10 a formed bythe wireless power transmitter 100. However, the wireless powertransmitter 100 may also transmit data to the wireless power receiver200 by a similar method.

That is, the power transmission control unit 112 may control themodulation/demodulation unit 113 to modulate data, which is to betransmitted to the wireless power receiver 200, such that the data canbe included in the carrier signal 10 a. Here, the power receptioncontrol unit 292 of the wireless power receiver 200 may control themodulation/demodulation unit 293 to execute demodulation so as toacquire data from the modulated carrier signal 10 a.

Packet Format

Hereinafter, description will be given of a structure of a packet usedin communication using a wireless power signal according to theexemplary embodiments disclosed herein.

FIG. 12 is a view illustrating a packet including a power controlmessage used in a contactless (wireless) power transfer method accordingto the embodiments disclosed herein.

As illustrated in FIG. 12A, the wireless power transmitter 100 and thewireless power receiver 200 may transmit and receive data desired totransmit in a form of a command packet (command_packet) 510. The commandpacket 510 may include a header 511 and a message 512.

The header 511 may include a field indicating a type of data included inthe message 512. Size and type of the message may be decided based on avalue of the field which indicates the type of data.

The header 511 may include an address field for identifying atransmitter (originator) of the packet. For example, the address fieldmay indicate an identifier of the wireless power receiver 200 or anidentifier of a group to which the wireless power receiver 200 belongs.When the wireless power receiver 200 transmits the packet 510, thewireless power receiver 200 may generate the packet 510 such that theaddress field can indicate identification information related to thereceiver 200 itself.

The message 512 may include data that the originator of the packet 510desires to transmit. The data included in the message 512 may be areport, a request or a response for the other party.

According to one exemplary embodiment, the command packet 510 may beconfigured as illustrated in FIG. 12B. The header 511 included in thecommand packet 510 may be represented with a predetermined size. Forexample, the header 511 may have a 2-byte size.

The header 511 may include a reception address field. For example, thereception address field may have a 6-bit size.

The header 511 may include an operation command field (OCF) or anoperation group field (OGF). The OGF is a value given for each group ofcommands for the wireless power receiver 200, and the OCF is a valuegiven for each command existing in each group in which the wirelesspower receiver 200 is included.

The message 512 may be divided into a length field 5121 of a parameterand a value field 5122 of the parameter. That is, the originator of thepacket 510 may generate the message by a length-value pair (5121 a-5122a, etc.) of at least one parameter, which is required to represent datadesired to transmit.

Referring to FIG. 12C, the wireless power transmitter 100 and thewireless power receiver 200 may transmit and receive the data in a formof a packet which further has a preamble 520 and a checksum 530 added tothe command packet 510.

The preamble 520 may be used to perform synchronization with datareceived by the wireless power transmitter 100 and detect the start bitof the header 520. The preamble 520 may be configured to repeat the samebit. For instance, the preamble 520 may be configured such that data bit1 according to the DBP encoding is repeated eleven to twenty five times.

The checksum 530 may be used to detect an error that can be occurred inthe command packet 510 while transmitting a power control message.

Operation Phases

Hereinafter, description will be given of operation phases of thewireless power transmitter 100 and the wireless power receiver 200.

FIG. 13 illustrates the operation phases of the wireless powertransmitter 100 and the wireless power receiver 200 according to theembodiments disclosed herein. Furthermore, FIGS. 14 to 18 illustrate thestructures of packets including a power control message between thewireless power transmitter 100 and the wireless power receiver 200.

Referring to FIG. 13, the operation phases of the wireless powertransmitter 100 and the wireless power receiver 200 for wireless powertransfer may be divided into a selection phase 610, a ping phase 620, anidentification and configuration phase 630, and a power transfer phase640.

The wireless power transmitter 100 detects whether or not objects existwithin a range that the wireless power transmitter 100 can transmitpower in a wireless manner in the selection phase 610, and the wirelesspower transmitter 100 sends a detection signal to the detected objectand the wireless power receiver 200 sends a response to the detectionsignal in the ping phase 620.

Furthermore, the wireless power transmitter 100 identifies the wirelesspower receiver 200 selected through the previous states and acquiresconfiguration information for power transmission in the identificationand configuration phase 630. The wireless power transmitter 100transmits power to the wireless power receiver 200 while controllingpower transmitted in response to a control message received from thewireless power receiver 200 in the power transfer phase 640.

Hereinafter, each of the operation phases will be described in detail.

1) Selection Phase

The wireless power transmitter 100 in the selection phase 610 performs adetection process to select the wireless power receiver 200 existingwithin a detection area. The detection area, as described above, refersto a region in which an object within the relevant area can affect onthe characteristic of the power of the power conversion unit 111.Compared to the ping phase 620, the detection process for selecting thewireless power receiver 200 in the selection phase 610 is a process ofdetecting a change of the power amount for forming a wireless powersignal in the power conversion unit at the side of the wireless powertransmitter 100 to check whether any object exists within apredetermined range, instead of the scheme of receiving a response fromthe wireless power receiver 200 using a power control message. Thedetection process in the selection phase 610 may be referred to as ananalog ping process in the aspect of detecting an object using awireless power signal without using a packet in a digital format in theping phase 620 which will be described later.

The wireless power transmitter 100 in the selection phase 610 can detectthat an object comes in or out within the detection area. Furthermore,the wireless power transmitter 100 can distinguish the wireless powerreceiver 200 capable of transferring power in a wireless manner fromother objects (for example, a key, a coin, etc.) among objects locatedwithin the detection area.

As described above, a distance that can transmit power in a wirelessmanner may be different according to the inductive coupling method andresonance coupling method, and thus the detection area for detecting anobject in the selection phase 610 may be different from one another.

First, in case where power is transmitted according to the inductivecoupling method, the wireless power transmitter 100 in the selectionphase 610 can monitor an interface surface (not shown) to detect thealignment and removal of objects.

Furthermore, the wireless power transmitter 100 may detect the locationof the wireless power receiver 200 placed on an upper portion of theinterface surface. As described above, the wireless power transmitter100 formed to include one or more transmitting coils may perform theprocess of entering the ping phase 620 in the selection phase 610, andchecking whether or not a response to the detection signal istransmitted from the object using each coil in the ping phase 620 orsubsequently entering the identification state 630 to check whetheridentification information is transmitted from the object. The wirelesspower transmitter 100 may determine a coil to be used for contactlesspower transfer based on the detected location of the wireless powerreceiver 200 acquired through the foregoing process.

Furthermore, when power is transmitted according to the resonancecoupling method, the wireless power transmitter 100 in the selectionphase 610 can detect an object by detecting that any one of a frequency,a current and a voltage of the power conversion unit is changed due toan object located within the detection area.

On the other hand, the wireless power transmitter 100 in the selectionphase 610 may detect an object by at least any one of the detectionmethods using the inductive coupling method and resonance couplingmethod. The wireless power transmitter 100 may perform an objectdetection process according to each power transmission method, andsubsequently select a method of detecting the object from the couplingmethods for contactless power transfer to advance to other states 620,630, 640.

On the other hand, for the wireless power transmitter 100, a wirelesspower signal formed to detect an object in the selection phase 610 and awireless power signal formed to perform digital detection,identification, configuration and power transmission in the subsequentstates 620, 630, 640 may have a different characteristic in thefrequency, strength, and the like. It is because the selection phase 610of the wireless power transmitter 100 corresponds to an idle state fordetecting an object, thereby allowing the wireless power transmitter 100to reduce consumption power in the idle state or generate a specializedsignal for effectively detecting an object.

2) Ping Phase

The wireless power transmitter 100 in the ping phase 620 performs aprocess of detecting the wireless power receiver 200 existing within thedetection area through a power control message. Compared to thedetection process of the wireless power receiver 200 using acharacteristic of the wireless power signal and the like in theselection phase 610, the detection process in the ping phase 620 may bereferred to as a digital ping process.

The wireless power transmitter 100 in the ping phase 620 forms awireless power signal to detect the wireless power receiver 200,modulates the wireless power signal modulated by the wireless powerreceiver 200, and acquires a power control message in a digital dataformat corresponding to a response to the detection signal from themodulated wireless power signal. The wireless power transmitter 100 mayreceive a power control message corresponding to the response to thedetection signal to recognize the wireless power receiver 200 which is asubject of power transmission.

The detection signal formed to allowing the wireless power transmitter100 in the ping phase 620 to perform a digital detection process may bea wireless power signal formed by applying a power signal at a specificoperating point for a predetermined period of time. The operating pointmay denote a frequency, duty cycle, and amplitude of the voltage appliedto the transmitting (Tx) coil. The wireless power transmitter 100 maygenerate the detection signal generated by applying the power signal ata specific operating point for a predetermined period of time, andattempt to receive a power control message from the wireless powerreceiver 200.

On the other hand, the power control message corresponding to a responseto the detection signal may be a message indicating strength of thewireless power signal received by the wireless power receiver 200. Forexample, the wireless power receiver 200 may transmit a signal strengthpacket 5100 including a message indicating the received strength of thewireless power signal as a response to the detection signal asillustrated in FIG. 14. The packet 5100 may include a header 5120 fornotifying a packet indicating the signal strength and a message 5130indicating strength of the power signal received by the wireless powerreceiver 200. The strength of the power signal within the message 5130may be a value indicating a degree of inductive coupling or resonancecoupling for power transmission between the wireless power transmitter100 and the wireless power receiver 200.

The wireless power transmitter 100 may receive a response message to thedetection signal to find the wireless power receiver 200, and thenextend the digital detection process to enter the identification andconfiguration phase 630. In other words, the wireless power transmitter100 maintains the power signal at a specific operating point subsequentto finding the wireless power receiver 200 to receive a power controlmessage required in the identification and configuration phase 630.

However, if the wireless power transmitter 100 is not able to find thewireless power receiver 200 to which power can be transferred, then theoperation phase of the wireless power transmitter 100 will be returnedto the selection phase 610.

3) Identification and Configuration Phase

The wireless power transmitter 100 in the identification andconfiguration phase 630 may receive identification information and/orconfiguration information transmitted by the wireless power receiver200, thereby controlling power transmission to be effectively carriedout.

The wireless power receiver 200 in the identification and configurationphase 630 may transmit a power control message including its ownidentification information. For this purpose, the wireless powerreceiver 200, for instance, may transmit an identification packet 5200including a message indicating the identification information of thewireless power receiver 200 as illustrated in FIG. 15A. The packet 5200may include a header 5220 for notifying a packet indicatingidentification information and a message 5230 including theidentification information of the electronic device. The message 5230may include information (2531 and 5232) indicating a version of thecontract for contactless power transfer, information 5233 foridentifying a manufacturer of the wireless power receiver 200,information 5234 indicating the presence or absence of an extendeddevice identifier, and a basic device identifier 5235. Furthermore, ifit is displayed that an extended device identifier exists in theinformation 5234 indicating the presence or absence of an extendeddevice identifier, then an extended identification packet 5300 includingthe extended device identifier as illustrated in FIG. 15B will betransmitted in a separate manner. The packet 5300 may include a header5320 for notifying a packet indicating an extended device identifier anda message 5330 including the extended device identifier. When theextended device identifier is used as described above, information basedon the manufacturer's identification information 5233, the basic deviceidentifier 5235 and the extended device identifier 5330 will be used toidentify the wireless power receiver 200.

The wireless power receiver 200 may transmit a power control messageincluding information on expected maximum power in the identificationand configuration phase 630. To this end, the wireless power receiver200, for instance, may transmit a configuration packet 5400 asillustrated in FIG. 16. The packet may include a header 5420 fornotifying that it is a configuration packet and a message 5430 includinginformation on the expected maximum power. The message 5430 may includepower class 5431, information 5432 on expected maximum power, anindicator 5433 indicating a method of determining a current of a maincell at the side of the wireless power transmitter, and the number 5434of optional configuration packets. The indicator 5433 may indicatewhether or not a current of the main cell at the side of the wirelesspower transmitter is determined as specified in the contract forwireless power transfer.

On the other hand, the wireless power transmitter 100 may generate apower transfer contract which is used for power charging with thewireless power receiver 200 based on the identification informationand/or configuration information. The power transfer contract mayinclude the limits of parameters determining a power transfercharacteristic in the power transfer phase 640.

The wireless power transmitter 100 may terminate the identification andconfiguration phase 630 and return to the selection phase 610 prior toentering the power transfer phase 640. For instance, the wireless powertransmitter 100 may terminate the identification and configuration phase630 to find another electronic device that can receive power in awireless manner.

4) Power Transfer Phase

The wireless power transmitter 100 in the power transfer phase 640transmits power to the wireless power receiver 200.

The wireless power transmitter 100 may receive a power control messagefrom the wireless power receiver 200 while transferring power, andcontrol a characteristic of the power applied to the transmitting coilin response to the received power control message. For example, thepower control message used to control a characteristic of the powerapplied to the transmitting coil may be included in a control errorpacket 5500 as illustrated in FIG. 17. The packet 5500 may include aheader 5520 for notifying that it is a control error packet and amessage 5530 including a control error value. The wireless powertransmitter 100 may control the power applied to the transmitting coilaccording to the control error value. In other words, a current appliedto the transmitting coil may be controlled so as to be maintained if thecontrol error value is “0,” reduced if the control error value is anegative value, and increased if the control error value is a positivevalue.

The wireless power transmitter 100 may monitor parameters within a powertransfer contract generated based on the identification informationand/or configuration information in the power transfer phase 640. As aresult of monitoring the parameters, if power transmission to thewireless power receiver 200 violates the limits included in the powertransfer contract, then the wireless power transmitter 100 may cancelthe power transmission and return to the selection phase 610.

The wireless power transmitter 100 may terminate the power transferphase 640 based on a power control message transferred from the wirelesspower receiver 200.

For example, if the charging of a battery has been completed whilecharging the battery using power transferred by the wireless powerreceiver 200, then a power control message for requesting the suspensionof wireless power transfer will be transferred to the wireless powertransmitter 100. In this case, the wireless power transmitter 100 mayreceive a message for requesting the suspension of the powertransmission, and then terminate wireless power transfer, and return tothe selection phase 610.

For another example, the wireless power receiver 200 may transfer apower control message for requesting renegotiation or reconfiguration toupdate the previously generated power transfer contract. The wirelesspower receiver 200 may transfer a message for requesting therenegotiation of the power transfer contract when it is required alarger or smaller amount of power than the currently transmitted poweramount. In this case, the wireless power transmitter 100 may receive amessage for requesting the renegotiation of the power transfer contract,and then terminate contactless power transfer, and return to theidentification and configuration phase 630.

To this end, a message transmitted by the wireless power receiver 200,for instance, may be an end power transfer packet 5600 as illustrated inFIG. 18. The packet 5600 may include a header 5620 for notifying that itis an end power transfer packet and a message 5630 including an endpower transfer code indicating the cause of the suspension. The endpower transfer code may indicate any one of charge complete, internalfault, over temperature, over voltage, over current, battery failure,reconfigure, no response, and unknown error.

Communication Method of Plural Electronic Devices

Hereinafter, description will be given of a method by which at least oneelectronic device performs communication with one wireless powertransmitter using wireless power signals.

FIG. 19 is a conceptual view illustrating a method of transferring powerto at least one wireless power receiver from a wireless powertransmitter.

The wireless power transmitter 100 may transmit power to one or morewireless power receivers 200 and 200′. FIG. 19 illustrates twoelectronic devices 200 and 200′, but the methods according to theexemplary embodiments disclosed herein may not be limited to the numberof electronic devices shown.

An active area and a detection area may be different according to thewireless power transfer method of the wireless power transmitter 100.Therefore, the wireless power transmitter 100 may determine whetherthere is a wireless power receiver located on the active area or thedetection area according to the resonance coupling method or a wirelesspower receiver located on the active area or the detection areaaccording to the induction coupling method. According to thedetermination result, the wireless power transmitter 100 which supportseach wireless power transfer method may change the power transfer methodfor each wireless power receiver.

In the wireless power transfer according to the exemplary embodimentsdisclosed herein, when the wireless power transmitter 100 transferspower to the one or more electronic devices 200 and 200′ according tothe same wireless power transfer method, the electronic devices 200 and200′ may perform communications through the wireless power signalswithout inter-collision.

Referring to FIG. 19, a wireless power signal 10 a generated by thewireless power transmitter 100 may arrive at the first electronic device200′ and the second electronic device 200, respectively. The first andsecond electronic devices 200′ and 200 may transmit wireless powermessages using the generated wireless power signal 10 a.

The first electronic device 200′ and the second electronic device 200may operate as wireless power receivers for receiving a wireless powersignal. The wireless power receiver in accordance with the exemplaryembodiments disclosed herein may include a power receiving unit 291′,291 to receive the generated wireless power signal, amodulation/demodulation unit 293′, 293 to modulate or demodulate thereceived wireless power signal, and a controller 292′, 292 to controleach component of the wireless power receiver.

Hereinafter, a wireless power transmitter performing many-to-onecommunication, a control method of the wireless power transmitterperforming many-to-one communication, and a wireless charging station(or wireless power transmission system) performing many-to-onecommunication will be described in more detail with reference to theaccompanying drawings.

FIGS. 20A, 20B and 20C are structural views illustrating a framestructure for performing communication according to the presentdisclosure. Furthermore, FIG. 21a and FIG. 21b illustrate a sync patternaccording to the present disclosure. FIG. 22 illustrates the operationstates of a wireless power transmitter and a wireless power receiverthat perform many-to-one communication. Furthermore, FIG. 23 illustratesa control information packet, and FIG. 24 illustrates an identificationdata packet, and FIG. 25 illustrates a configuration packet, and FIG. 26illustrates an SRQ data packet, and FIG. 27 illustrates an EPT packet.

The wireless power transmitter 100 according to an embodiment of thepresent disclosure may transmit power in a wireless manner through thepower conversion unit 111. Here, the wireless power transmitter 100 maytransmit power using at least one of an inductive coupling method and aresonance coupling method.

The power conversion unit 111 of the wireless power transmitter 100 mayinclude a single coil and a plurality of coils. The wireless powertransmitter 100 performing a communication method which will bedescribed below may applicable both cases where the power conversionunit 111 is configured with a single coil or plurality of coils.

Furthermore, the power conversion unit 111 may transmit a wireless powersignal to perform communication between the wireless power transmitter100 and the wireless power receiver 200. More specifically, wirelesspower signal generated from the power conversion unit 111 may bemodulated and demodulated through the modulation/demodulation unit 113,and transmitted as a packet to the wireless power receiver. Themodulation and demodulation method will be substituted by the earlierdescription of FIG. 9.

On the other hand, the wireless power transmitter 100 may performcommunication with one wireless power receiver or perform communicationwith a plurality of wireless power receivers.

Here, a method of performing communication with one wireless powerreceiver may be defined as an exclusive mode, and a method of performingcommunication with one or more wireless power receivers may be definedas a shared mode. The exclusive mode may have a magnetic field couplingcoefficient of 0.3 or above, and the shared mode has a magnetic fieldcoupling coefficient of 0.1 or less.

The wireless power receiver 200 may receive a power signal from thewireless power transmitter 100 when the wireless power receiver 200 islocated within a functional area in which the function of the wirelesspower transmitter 100 is carried out. Here, the wireless power receiver200 may start the operation as a selection phase based on the wirelesspower signal.

During the selection phase, the wireless power receiver 200 may operatein either one of an exclusive mode and a shared mode according towhether or not there exists a specific signal within the wireless powersignal received from the wireless power transmitter 100. Here, thespecific signal may be frequency shift keying (FSK). The FSK signal maybe a signal for providing synchronization information and otherinformation to the wireless power receiver.

More specifically, the wireless power receiver 200 may start theoperation in the selection phase and then immediately sense theexistence of FSK signals within the wireless power signal. If thewireless power receiver 200 detects the FSK signal subsequent to a timepoint at which the wireless power signal is received and prior to thepassage of a predetermined period of time, then the wireless powerreceiver 200 may carry out an introduction phase of the shared mode.Here, the predetermined period of time may denote a digital ping time ofthe exclusive mode, for example, 65 ms.

On the contrary, when the wireless power receiver 200 does not detectthe FSK signal, the wireless power receiver 200 may operate as anexclusive mode. In this case, the wireless power receiver 200 may carryout the operation phases described in FIG. 13.

Hereinafter, a method of allowing the wireless power receiver 200 tocarry out a shared mode will be described in more detail with referenceto the accompanying drawings.

As illustrated in FIGS. 20A, 20B and 20C, when the wireless powerreceiver operates in a shared mode, the wireless power transmitter 100may provide a plurality of slots (or time slots) to performcommunication with one or more wireless power receivers. The slots maybe slots having a length suitable to the transmission of data packets inthe wireless power receiver.

The plurality of slots may be slots having a fixed length, respectively.Furthermore, the wireless power transmitter 100 may transmit a syncpattern to the wireless power receiver between two consecutive slots ofthe plurality of slots.

The sync pattern may be transmitted between the plurality of slots toperform the role of separating between the consecutive slots.Furthermore, the sync pattern may perform the role of optimizingcommunication between the wireless power transmitter 100 and thewireless power receiver. For example, the sync pattern may provideinformation on a collision occurrence and a secured standby time to thewireless power receiver, thereby performing the optimization ofcommunication.

On the other hand, the plurality of slots may form a frame structurehaving a fixed length. In other words, the frame may be configured witha plurality of slots.

Here, the frame may denote a communication unit for transmitting andreceiving information while transmitting power. The frame may have apreset length. For example, the single frame may have a time interval of1 sec (1000 ms).

In other words, the wireless power transmitter 100 may performcommunication in the unit of frames. In other words, the wireless powertransmitter 100 may perform communication through a first frame for onesecond, and perform communication through a second frame for thefollowing one second subsequent to the passage of the one second.

The frame may be started with a sync pattern. In other words, the syncpattern may exist between frames to perform the role of separatingbetween the frames. Furthermore the sync pattern may be located at themost front side of the frame to perform the role of notifying a start ofthe frame. In other words, the wireless power receiver may sense a startof the frame through a sync pattern received from the wireless powertransmitter. Here, a start bit of the sync pattern may indicate a startof the frame.

Furthermore, the frame may be configured with a slot having a presettime interval (for example, 50 ms) subsequent to the sync pattern. Theslot subsequent to the sync pattern may be referred to as a measurementslot or measurement window. The measurement slot may be a slot in whichcommunication between the wireless power transmitter and the wirelesspower receiver is not carried out, namely, a slot maintained as a freecommunication slot.

More specifically, the wireless power transmitter may determine powertransmitted to the wireless power receiver within the measurement slot.Furthermore, each wireless power receiver may determine an amount ofpower received by the wireless power receiver itself to transmit thereceived amount of power to the wireless power transmitter within themeasurement slot.

In other words, the wireless power transmitter may recognize an amountof power transmitted to the wireless power receiver through themeasurement slot, and control an amount of power to be transmittedafterwards.

In the shared mode below, a sync pattern indicating a start of the frameand the measurement slot may be provided in all frames.

The frame may be configured with various forms. A number of slotsconstituting the frame, a length of the slots, a length of the frame orthe like may be changed by a designer's design. For example, the framemay be configured with 10 slots and 10 sync patterns having the sametime interval. For another example, the frame may be configured with 8slots and 1 sync pattern having the same time interval. For stillanother example, the frame may be configured with a plurality of slotshaving different time intervals.

On the other hand, in the shared mode, different types of frames may beused at the same time. For example, a slotted frame having a pluralityof slots and a free-format frame with no specific format may be used inthe shared mode. More specifically, the slotted frame may be a frame forallowing the transmission of short data packets to the wireless powertransmitter 100 and the free-format frame may be a frame that is notprovided with a plurality of slots to allow the transmission of longdata packets.

On the other hand, the slotted frame and the free-format frame may bechanged to various names by those skilled in the art. For example, theslotted frame and the free-format frame may be changed and named achannel frame and a message frame, respectively.

More specifically, referring to FIG. 20A, the slotted frame may includea sync pattern indicating a start of the slot, a measurement slot, nineslots, and an optional sync pattern having the same time interval priorto each of the nine slots. Here, the optional sync pattern is adifferent sync pattern from the foregoing sync pattern indicating astart of the frame. More specifically, the optional sync pattern mayindicate information associated with any adjoining slots (twoconsecutive slots located at both sides of the sync pattern) withoutindicating a start of the frame.

In other words, referring to FIG. 20A, a sync pattern may berespectively located between two consecutive slots among the nine slots.In this case, the sync pattern may provide information associated withthe two consecutive slots.

Furthermore, the nine slots and sync patterns provided prior to the nineslots, respectively, may have the same time interval. For example,referring to FIG. 20A, the nine slots may have a time interval of 50 ms.In addition, the nine sync patterns may also have a time length of 50ms.

On the other hand, the slot frame may have a different type from theforegoing description. For example, referring to FIG. 20B, the slotframe may be configured with a sync pattern indicating a start of theslot, a measurement slot and a plurality of slots. In other words,referring to FIG. 20B, the slot frame may have only a sync patternindicating a start of the frame without having a sync pattern betweentwo consecutive slots.

In this case, the sync pattern indicating a start of the frame mayinclude status information of a plurality of slots constituting the slotframe. For example, the sync pattern may include information on whetheror not each of the plurality of slots is allocated to a wireless powerreceiver.

Furthermore, referring to FIG. 20B, the slot frame may be configuredwith slots having the same time interval. Here, the time interval of theslots may be determined by a number of wireless power receivers that canbe charged by the wireless power transmitter 100 at the same time. Forexample, when the wireless power transmitter 100 is able to transferpower to eight wireless power receivers at the same time, one slot mayhave a time interval of 125 ms.

On the other hand, referring to FIG. 20B, even without having a syncpattern between slots, the wireless power transmitter 100 may transmitinformation indicating the status of adjoining slots to the wirelesspower receiver between the slots. For example, information indicatingthe status of the slots may be a slot occupied indicator (SOI), astart-up slot indicator (SSI), a slot free indicator (SFI), informationon whether or not communication from the wireless power receiver isefficiently carried out within a slot (ACK, NAK, no communicationsignal, communication error signal) or the like.

In other words, the slot frame may transmit information betweenadjoining slots to the wireless power receiver regardless of whether ornot a sync pattern is provided between slots. In other words, thewireless power transmitter 100 may provide the information in the formof a sync pattern or sync bit to the wireless power receiver. Throughthis, the wireless power receiver may know the status information ofeach slot to efficiently perform communication with the wireless powertransmitter.

The following description may be all applicable to the slot frame in thesimilar manner regardless of the type of the slot frame.

A plurality of slots constituting the slot frame may be provided toperform communication between one wireless power transmitter and one ormore wireless power receivers.

The plurality of slots may be configured with at least one of anallocated slot, a free slot, a measurement slot and a locked slot.

The allocated slot may be a slot used by a specific wireless powerreceiver. More specifically, a different wireless power receiver otherthan the specific wireless power receiver may be limited to transmitinformation to the wireless power transmitter within a slot allocated tothe specific wireless power receiver.

The free slot may be a slot that is freely used by any wireless powerreceiver. In other words, the free slot may be a slot provided for anywireless power receiver to transmit information to the wireless powertransmitter within the free slot.

The measurement slot is a slot in which communication with the wirelesspower receiver is not carried out to measure power that has beentransmitted and received. More specifically, the measurement slot may bea slot provided to transmit and receive power information between thewireless power transmitter and the wireless power receiver.

The locked slot may be a slot that is temporarily locked to be used by aspecific wireless power receiver. More specifically, the locked slot maybe a slot in which only a specific wireless power receiver can accessduring a start-up sequence to allow the specific wireless power receiverto perform the start-up sequence. The start-up sequence will bedescribed below in more detail.

The locked slot may be limited to access a different wireless powerreceiver other than the specific wireless power receiver. In otherwords, the different wireless power receiver may be limited to transmitinformation within the locked slot in a state that the locked slot isprovided.

On the other hand, the locked slot may be a temporarily provided, andthus when the start-up sequence of the specific wireless power receiveris completed, it may be provided as a free slot again.

Each of the plurality of slots may have a limited time length. Forexample, each of the plurality of slots may have a time length of 50 ms.Since the each slot has 50 ms, the wireless power receiver can transmitdata of approximately 5 bytes for each slot.

The structure of the slot frame may be easily changed by those skilledin the art, and the following description of a communication scheme maybe carried out in the same manner regardless of the structure of theslot frame.

Furthermore, referring to FIG. 20C, the free type frame may not have aspecific form other than a sync pattern indicating a start of the frameand a measurement slot. In other words, the free type frame is toperform a different role from the slot frame, and for example, may beused to perform communication of long data packets (for example,optionally proprietary information packets) between the wireless powertransmitter and wireless power receiver or perform the role of selectingany one of a plurality of coils in the wireless power transmitterconfigured with the plurality of coils.

In the above, frame structures have been described.

Hereinafter, a sync pattern contained in each frame will be described inmore detail with reference to the accompanying drawings.

As a signal containing the information of slots, the sync pattern may beimplemented in various forms. For example, the sync pattern may beimplemented with a pattern or packet.

Furthermore, at least one or more sync patterns may exist in the framestructure. For example, the sync pattern may be provided at a front sideof each slot or provided only at the most front side of the frame. Forexample, the sync pattern may be provided at the most front of the frameand between each slot. For another example, the sync pattern may beprovided only at the most front side of the frame within the frameconfigured with a plurality of slots.

The sync pattern may include various information. For example, the syncpattern may include status information of a slot, status information ofa frame, a structure of frame, communication execution statusinformation, and the like.

For example, referring to FIG. 21a , the sync pattern may be configuredwith a preamble, a start bit, a response field, a type field, an infofield, and a parity bit. In FIG. 21a , the start bit is illustrated asZERO.

More specifically, the preamble may be configured with consecutive bits,and set to all “0”s. In other words, the preamble may be bits foradjusting a time length of the sync pattern.

The number of bits constituting the preamble may dependent on anoperating frequency such that the length of a sync pattern is theclosest to 50 ms but within a range not exceeding 50 ms. For example,the sync pattern is configured with two preamble bits when the operatingfrequency is 100 kHz, and configured with three preamble bits when theoperating frequency is 105 kHz.

As a bit subsequent to the preamble, the start bit may denote ZERO. TheZERO may be a bit indicating the type of sync pattern. Here, the type ofsync pattern may include a frame sync including information associatedwith a frame and a slot sync including the information of a slot. Inother words, the sync pattern may be a frame sync located betweenconsecutive frames to indicate a start of the frame or a slot synclocated between consecutive slots among a plurality of slots to includeinformation associated with the consecutive slots. For example, it maydenote a slot sync in which the relevant slot is located between slotswhen the ZERO is “0”, and denote a frame sync in which the relevant syncpattern is located frames when the ZERO is “1”.

As the last bit of a sync pattern, the parity bit may indicate the datafields (i.e., a response field, a type field, an information field) ofthe sync pattern. For example, the parity bit may be “1” if the numberof bits constituting the data fields of the sync pattern is an evennumber, and “0” otherwise (i.e., odd number).

The response field may include the response information of the wirelesspower transmitter with regard to communication with the wireless powerreceiver within a slot prior to the sync pattern. For example, theresponse field may have “00” when the execution of communication withthe wireless power receiver is not sensed. Furthermore, the responsefield may have “01” when a communication error is sensed whilecommunicating with the wireless power receiver. The communication errormay be a case where a collision between two or more wireless powerreceivers occurs when the two or more wireless power receivers attemptto access one slot.

Furthermore, the response field may include information indicatingwhether or not a data packet is correctly received from the wirelesspower receiver. More specifically, the response field may be “10” (notacknowledge, NAK) if the wireless power transmitter denies the datapacket, and “11” (acknowledge, ACK) when the wireless power transmitterconfirms the data packet.

The type field may indicate a type of sync pattern. More specifically,the type field may have “1” indicating a frame sync when the syncpattern is a first sync pattern of the frame (i.e., when located priorto a measurement slot as a first sync pattern of the frame).

Furthermore, the type field may have “0” indicating a slot sync when thesync pattern is not a first sync pattern of the frame.

Furthermore, the information field may determine the meaning of itsvalue according to the type of sync pattern indicated by the type field.For example, the meaning of the information field may indicate a type offrame when the type field is “1” (i.e., when indicates a frame sync). Inother words, the information field may indicate whether or not a currentframe is a slotted frame or free-format frame. For example, it mayindicate a slot frame if the information field is “00”, and afree-format frame if the information field is “01”.

On the contrary, when the type field is “0” (i.e., slot sync), theinformation field may indicate the status of a next slot locatedsubsequent to the sync pattern. More specifically, the information fieldmay have “00” if the next slot is a slot allocated to a specificwireless power receiver, “01” when it is a locked slot to be temporarilyused by the specific wireless power receiver, or “10” when it is a slotto be freely used by any wireless power receiver.

For another example, referring to FIG. 21b , the sync pattern includesinformation of plurality of slots which is whether or not the pluralityof slots is allocated. Here, the sync pattern is located at a startposition of the frame.

Also, the sync pattern has bits corresponding to the plurality of slots,respectively. For example, the number of bit included in the syncpattern is 9, when the number of plurality of slots is 9.

Also, the bits represent whether not the plurality of slots isallocated. For example, a bit has ‘0’, when a slot of the plurality ofslots is allocated, otherwise, bit has ‘1’.

In the above, the structure of a sync pattern has been described.

Hereinafter, the operating phase of the wireless power receiver in ashared mode will be described in more detail.

Referring to FIG. 22, the wireless power receiver operated in a sharedmode may operate in any one of a selection phase 2000, an introductionphase 2010, a configuration phase 2020, a negotiation phase 2030 and apower transfer phase 2040.

First, the wireless power transmitter 100 according to an embodiment ofthe present disclosure may transmit a wireless power signal to sense thewireless power receiver. In other words, as described above in FIG. 13,the process of sensing the wireless power receiver using such a wirelesspower signal may be referred to as analog ping.

On the other hand, the wireless power receiver that has received thewireless power signal may enter the selection phase 2000. The wirelesspower receiver that has entered the selection phase 2000 may sense theexistence of a FSK signal on the wireless power signal as describedabove.

In other words, the wireless power receiver may perform communication inany one of an exclusive mode and a shared mode according to theexistence or non-existence of the FSK signal.

More specifically, the wireless power receiver operates in a shared modeif a FSK signal is included in the wireless power signal, and otherwiseoperates in an exclusive mode.

If the wireless power receiver operates in an exclusive mode, then thewireless power receiver may carry out the operation phases described inFIG. 13.

If the wireless power receiver operates in a shared mode, then thewireless power receiver may enter the introduction phase 2010. Duringthe introduction phase 2010, the wireless power receiver may transmit acontrol information packet to the wireless power transmitter to transmitthe control information (CI) packet 2100 during the configuration phase,negotiation phase and power transfer phase. The control informationpacket may have a header and information associated with control. Forexample, the header may be “0x53” in the control information packet.

Referring to FIG. 23, the control information (CI) packet 2100 mayinclude power value information received by the wireless power receiver(received power value), control error value information on powertransfer (control error value), power transfer stop request information(fault), and the like.

Here, the wireless power transmitter 100 may control an amount of powertransmitted to the wireless power receiver based on the controlinformation (CI) packet. For example, as control error informationincreases or decreases, the wireless power transmitter 100 may increaseor decrease the amount of current of a coil constituting the powerconversion unit 111 of the wireless power transmitter. For anotherexample, the wireless power transmitter may use the received power valueinformation as an average value of the measurement slot.

On the other hand, the wireless power transmitter 100 may receive thecontrol information (CI) packet from the wireless power receiver withinany one of the plurality of slots. For example, the wireless powertransmitter may receive the control information from the wireless powerreceiver within a first slot among the plurality of slots of the firstframe.

The wireless power transmitter 100 may transmit an acknowledge (ACK)signal when the first slot is available, and transmit a not-acknowledge(NAK) signal when the first slot is not available.

More specifically, the wireless power transmitter 100 may transmit anACK signal to the wireless power receiver when the control informationpacket is successfully received within the first slot, and transmit aNAK signal when a wireless power receiver different from the wirelesspower receiver that has transmitted the control information (CI) packetcarries out the configuration phase 2020 or negotiation phase 2030within the first slot.

If an ACK signal is transmitted to the wireless power receiver, then thewireless power transmitter 100 may allocate the first slot to thewireless power receiver. Here, the wireless power receiver may transmita control information (CI) packet using the allocated first slot duringthe configuration phase 2020, negotiation phase 2030 and power transferphase 2040. In other words, when the ACK signal is received, thewireless power receiver may always transmit a control information (CI)packet regardless of the operation phase of the wireless power receiver.

On the contrary, when a NAK signal is transmitted to the wireless powerreceiver, the wireless power transmitter 100 may not allocate the firstslot to the wireless power receiver. Here, the wireless power receiverto which the first slot is not allocated may transmit the controlinformation (CI) packet again within any one of the remaining slotsother than the first slot until receiving an ACK signal.

On the other hand, the wireless power transmitter 100 may transmit anACK signal to provide locked slots for the exclusive use of the wirelesspower receiver when the wireless power receiver is allowed to enter theconfiguration phase 2020. More specifically, the wireless powertransmitter 100 may provide locked slots to the wireless power receiverin which their access is limited to a wireless power receiver differentfrom the wireless power receiver. In this case, the wireless powerreceiver may carry out the configuration phase and negotiation phasewithout any collision with the different wireless power receiver usingthe locked slots.

The configuration phase 2020 may be a phase in which the wireless powerreceiver transmits information associated with the configuration phase2020 to allow the wireless power receiver to efficiently receive power.More specifically, the configuration phase 2020 may be a phase in whichthe identification information of the wireless power receiver isprovided to the wireless power transmitter 100 to allow the wirelesspower transmitter 100 to identify each wireless power receiver in ashared mode.

In other words, during the configuration phase 2020, the wireless powertransmitter 100 may receive information associated with theconfiguration phase 2020 from the wireless power receiver within thelocked slots. Here, information associated with the configuration phase2020 may include identification data packets, optionally proprietarydata packets, configuration (CFG) packets, and the like.

Referring to FIG. 24, the identification data packets may include anIDHI packet and an IDLO packet. The header of the IDHI packet may have“0x54” and the header of the IDLO packet may have “0x55”. Furthermore,the identification data packets may include unique identification (ID)information for the identification of the wireless power receiver,version information of a wireless power transfer contract used for thewireless power receiver, and cyclic redundancy check (CRC) informationfor determining an error of the identification information.

As data packets above 5 bytes, optionally proprietary data packets maybe received at the wireless power receiver through a free-format frame.As information associated with the proprietorship of the wireless powerreceiver, the optionally proprietary data packets may be manufacturerinformation of the wireless power receiver or the like.

Referring to FIG. 25, the configuration (CFG) packet 2700 may includecount information including a number of optional data packets, depthinformation including a scaling factor for calculating a FSK modulationdepth, maximum power information, power class information of thewireless power receiver indicating any one of power levels, low power,medium power and high power, negotiation (Neg) information provided onlyin an exclusive mode, an indicator (prop) indicating a method ofdetermining a current of a major cell at the side of the wireless powertransmitter, polarity information (pol) of a FSK signal, window offsetinformation, and the like.

The wireless power transmitter may respond to the wireless powerreceiver using any one of an ACK signal, a NAK signal, a nocommunication signal and a communication error signal.

More specifically, the wireless power transmitter may transmit a NAKsignal to the wireless power receiver when a cyclic redundancy check(CRC) error is sensed on the identification data packets (IDHI, IDLO),and otherwise transmit an ACK signal.

On the other hand, when the wireless power receiver returns to theconfiguration phase 2020 again from the power transfer phase 2040 basedon reconfiguration request information (EPT/reconfigure packet) toreconfigure a power transfer contract, the identification data packetsmay be transmitted or not transmitted to the wireless power transmitter100.

Furthermore, when the optionally proprietary data packets cannot berecognized since they differ from preset data, the wireless powertransmitter may transmit a NAK signal to the wireless power receiver,and otherwise transmit an ACK signal or NAK signal with respect tospecific proprietary data packets in an appropriate manner. Meanwhile,in order to receive the optionally proprietary data packets, thewireless power receiver may transmit insert free-format frameinformation for requesting a free-format frame to the wireless powertransmitter to use the free-format frame.

Furthermore, when a configuration (CFG) packet is received, the wirelesspower transmitter may transmit an ACK signal in response to informationincluded in the configuration packet.

If the wireless power transmitter transmits the no communication signalor communication error signal with respect to information associatedwith the configuration phase 2020, then the wireless power receiver mayretransmit a data packet that has received the no communication signalor communication error signal.

The wireless power receiver may receives information associated with theconfiguration phase 2020, and then enter the negotiation phase 2030. Inother words, when a configuration (CFG) packet is received during theconfiguration phase 2020, the wireless power transmitter 100 may beallowed to enter the negotiation phase 2030.

The negotiation phase 2030 may be a phase in which the wireless powerreceiver transmits information associated with the negotiation phase2030 to the wireless power transmitter 100 to effectively transfer powerto the wireless power receiver. More specifically, the negotiation phase2030 may be a phase in which the wireless power receiver provides powerinformation to be transmitted to the wireless power receiver to thewireless power transmitter in a shared mode.

Here, the wireless power transmitter 100 may continuously provide lockedslots provided during the configuration phase 2020 even during thenegotiation phase 2030. In other words, the wireless power transmitter100 may provide the locked slots, thereby securing the progress of thenegotiation phase 2030 without any collision between the wireless powerreceiver and a wireless power receiver different from the wireless powerreceiver.

The wireless power receiver may transmit information associated with thenegotiation phase 2030 using the locked slots. In other words, thewireless power transmitter 100 may receive information associated withthe negotiation phase 2030 from the wireless power receiver within thelocked slots.

Here, the information associated with the negotiation phase 2030 mayinclude optionally proprietary data packets, negotiation data packets,and an end negotiation phase request (SRQ/en, end-negotiation) packet.The negotiation data packets may include specific request (SRQ) packetsand general request (GRQ) packets.

Referring to FIG. 26, the SRQ packet 2800 may include request groundinformation and request value information. Here, the request groundinformation may be any one of end negotiation information, guaranteedpower information, received power packet type information, modulationdepth information, maximum power information, and insert free-formatframe information. The request value information may include parameterinformation determined by the request ground information.

The end negotiation phase request packet may include information onrequesting the end of the negotiation phase 2030. When the endnegotiation phase request packet is transmitted, the wireless powerreceiver may end the negotiation phase 2030 and enter the power transferphase 2040.

When information associated with the negotiation phase 2030 is received,the wireless power transmitter 100 may respond to the wireless powerreceiver using any one of an ACK signal, a NAK signal, a nocommunication signal and a communication error signal.

More specifically, the wireless power transmitter 100 may transmit anACK signal or NAK signal to the wireless power receiver with respect tothe negotiation data packet.

Furthermore, when the optionally proprietary data packets cannot berecognized since they differ from preset data, the wireless powertransmitter may transmit a NAK signal to the wireless power receiver,and otherwise transmit an ACK signal or NAK signal in an appropriatemanner.

Furthermore, when the no communication signal or communication errorsignal is received with respect to information associated with thenegotiation phase 2030, the wireless power transmitter 100 mayretransmit data that has received the no communication signal orcommunication error signal.

On the other hand, when the reception of the information associated withthe negotiation phase 2030 is completed, the wireless power transmitter100 may enter the power transfer phase 2040. For example, when endnegotiation phase request packet (SRQ/en) is received, the wirelesspower transmitter 100 may transmit an ACK signal, and the wireless powerreceiver may enter the power transfer phase 2040.

Here, when the negotiation phase 2030 is completed, the wireless powertransmitter 100 may suspend the provision of the locked slots to thewireless power receiver.

The power transfer phase 2040 may denote a phase of transmitting powerin a wireless manner. The wireless power receiver may continuouslytransmit a control information (CI) packet through the allocated firstslot during the power transfer phase 2040. Furthermore, the wirelesspower receiver may freely transmit one or more data packets using freeslots among a plurality of slots.

More specifically, the wireless power receiver may transmit an end powertransfer packet, a charge status packet (CHS2), and proprietary datapackets during the power transfer phase 2040.

Referring to FIG. 27, the end power transfer packet 2900 may includerequest information and slot information of the end power transferpacket. The request information of the end power transfer packet mayinclude any one of charging complete information, internal faultinformation indicating a software or logic error, over-temperatureinformation, over voltage information, over current information, batteryfailure information indicating a battery defect, reconfigure requestinformation, no response information indicating no response to a controlinformation packet or control error packet, renegotiate requestinformation, and unknown information. The slot information may includenumber information of a slot allocated to the wireless power receiver.

Referring to FIG. 28, the charge status packet may include charge statusinformation and slot information. The charge status information may beinformation of a current charging amount of the wireless power receiver.For example, the charging status information may be charging percentageinformation. The slot information may include numeral information of aslot allocated to the wireless power receiver.

As data packets optionally generated from the wireless power receiver,the proprietary data packets may include manufacturer information or thelike of the wireless power receiver, for example.

On the other hand, the wireless power transmitter 100 may control thewireless power receiver based on end power transfer packet informationto the wireless power receiver. For example, when reconfigure requestinformation is included in the end power transfer packet, the wirelesspower receiver may return to the configuration phase 2020 again from thepower transfer phase 2040.

In the above, the operation phases of the wireless power receiver in ashared mode have been described.

Hereinafter, a method of performing communication using a slot allocatedto the wireless power transmitter and wireless power receiver will bedescribed in more detail with reference to the accompanying drawings.FIGS. 29, 30A and 30B illustrate a method of counting the position ofslots allocated to the wireless power transmitter and wireless powerreceiver in a shared mode.

The wireless power receiver may receive a wireless power signal from thewireless power transmitter. Here, the wireless power receiver may enterthe selection phase 2000 based on the reception of the wireless powersignal.

During the selection phase 2000, the wireless power receiver may sensethe existence or non-existence of a FSK signal within the wireless powersignal. If the FSK signal does not exist, the wireless power receivermay operate in an exclusive mode, and perform communication with thewireless power transmitter using a one-to-one communication scheme. Onthe contrary, when there exists the FSK signal, the wireless powerreceiver may operate in a shared mode, and enter the introduction phase2010.

During the introduction phase 2010, the wireless power receiver mayselect any one of a plurality of slots to transmit specific information(or a first packet) to the wireless power transmitter. Here, as presetinformation, the specific information may be at least one of controlinformation (CI) packet, signal strength (SS) packet, and slot numberpacket. For example, the information may be a control informationpacket.

The specific information may be transmitted to the power transmitter asa first data in the start-up sequence of the power receivers. Also, thespecific information is used as identification information of the powerreceivers.

Here, the plurality of slots may be sequentially provided to thewireless power receiver according to the flow of time. For example, whena time passes in a state that any one of the plurality of slots isprovided, another slot of the plurality of slots may be provided.

Furthermore, the wireless power receiver may randomly select any one ofthe sequentially provided plurality of slots.

On the other hand, when the specific information is received from thewireless power receiver within any one of a plurality of slots, thepower transmission control unit 112 of the wireless power transmittermay determine whether or not any one slot is available. Here, when theany one slot is available, the power transmission control unit 112 mayallocate the any one slot to the wireless power receiver. On thecontrary, when the any one slot is not available, the power transmissioncontrol unit 112 may not allocate the any one slot to the wireless powerreceiver.

Here, the allocation of a slot to the wireless power receiver may denotethe setting of the wireless power transmitter to receive onlyinformation transmitted from the wireless power receiver within theallocated slot. In other words, within the allocated slot, only specificinformation of the wireless power receiver allocated to the slot may bereceived, but the reception of the specific information transmitted froma different wireless power receiver other than the wireless powerreceiver may be limited.

A case where the any one slot is available may be a case where the anyone slot is not allocated to a wireless power receiver different fromthe wireless power receiver prior to the transmission of controlinformation of the wireless power receiver within the any one slot.

A case where the any one slot is not available may be a case where theany one slot is already allocated to a wireless power receiver differentfrom the wireless power receiver prior to the transmission of controlinformation of the wireless power receiver within the any one slot orthe control information of a wireless power receiver different from thewireless power receiver is received at the same time within the any oneslot.

Subsequent to the allocation of the slot, the power transmission controlunit 112 may perform communication with the wireless power receiverthrough the allocated slot. More specifically, the power transmissioncontrol unit 112 may receive specific information from the wirelesspower receiver within the allocated slot.

Furthermore, subsequent to the allocation of the slot, the powertransmission control unit 112 may provide at least part of the pluralityof slots to the wireless power receiver as locked slots.

The locked slots are slots temporarily provided for the progress of theconfiguration phase 2020 and negotiation phase 2030 of the wirelesspower receiver, and the wireless power receiver may carry out theconfiguration phase 2020 and negotiation phase 2030 using the lockedslots. Here, when the progress of the configuration phase 2020 andnegotiation phase 2030 is completed, the locked slots may be no longerprovided to the wireless power receiver.

Here, the power transmission control unit 112 may reserve the slotinformation of the allocated slot prior to the progress of thenegotiation phase 2030 and negotiation phase 2030. In other words,during the introduction phase 2010, the power transmission control unit112 may allocate any one of the plurality of slots to the wireless powerreceiver and then store the slot information of the any one slot.

The slot information may be information associated with the slot, suchas position information of the slot, unique identification informationof the slot, status information of the slot.

The position information of the slot may denote a distance to each sloton the basis of a frame sync indicating a start of a frame in the frameconfigured with the plurality of slots. For example, when the number ofthe plurality of slots is 9, each slot may have a distance of 1 to 9from the closest distance on the basis of the frame sync. Here, theframe sync may denote a sync pattern located at the most front side ofthe frame configured with the plurality of slots.

The unique identification information of the slot may denoteidentification information capable of identifying each of the pluralityof slots. For example, each slot may have different unique IDinformation.

The status information of the slot may be information associated withthe communication status of the slot such as whether or not the slot islocked.

Furthermore, when any one of the plurality of slots is allocated, thewireless power receiver may also store the slot information of the anyone slot. Here, the wireless power receiver may store the slotinformation of the any one slot prior to entering the configurationphase 2020. In other words, the wireless power receiver may store theslot information of the any one slot during the introduction phase 2010.

On the other hand, the power reception control unit 292 may calculatethe slot information of the any one slot to store the slot informationof the any one slot. For example, when the slot information is theposition information of the slot, the power reception control unit 292may calculate the position information of the slot.

More specifically, the power reception control unit 292 of the wirelesspower receiver may receive an ACK signal from the wireless powertransmitter in response to control information that has been transmittedto the wireless power transmitter. In this case, the power receptioncontrol unit 292 may determine that any one slot that has transmittedcontrol information is allocated.

Subsequent to the transmission of the ACK signal, the power receptioncontrol unit 292 may determine the position of the any one slot to storethe position information of the any one slot.

Here, the power reception control unit 292 may determine the position ofthe any one slot through various methods. For example, the powerreception control unit 292 may determine the position of the any oneslot through i) a method of receiving the identification (ID)information of the allocated slot from the wireless power transmitter,ii) a method of directly calculating the position of the allocated slot,and the like.

The method of receiving the slot information of the allocated slot fromthe wireless power transmitter is a method of allowing the wirelesspower transmitter to provide slot information to the wireless powerreceiver using a separate packet. In this case, the wireless powertransmitter may transmit slot information included within the ACK signalto the wireless power receiver or additionally transmit a separateidentification packet including slot information to the wireless powerreceiver during the introduction phase 2010.

When the slot information of the allocated slot is received from thewireless power transmitter, the power reception control unit 292 maydetermine the position of the slot based on the slot information. Forexample, when the slot information includes information indicating thatthe slot is a third slot, the power reception control unit 292 maydetermine that the position of the slot is a third one of the pluralityof slots.

Furthermore, the power reception control unit 292 may calculate a timefor transmitting control information to the wireless power transmitterbased on the position information of the slot. More specifically, thepower reception control unit 292 may determine a transmission time pointof the control information based on a time interval of each slot and theposition information of the slot with respect to the frame sync. Forexample, when the frame sync is received from the power transmitter, thepower reception control unit 292 may start to calculate the transmissiontime point of the control information with respect to a time point whichat the frame sync is received from the power transmitter.

The power reception control unit 292 may additionally consider a timeinterval of the frame sync indicating a start of a plurality of slotsand a time interval of the measurement slot together as a default valueto determine a transmission time point of the control information.

For example, when the slot is a third slot and the time interval of eachslot is 100 ms, and the default value is 100 ms, the power receptioncontrol unit 292 may determine a transmission time point of the controlinformation as a time between 400 ms and 500 ms.

Through this, the wireless power transmitter and wireless power receivermay know the position of a slot allocated to the wireless powerreceiver, respectively, to perform communication using the allocatedslot.

Hereinafter, a method of allowing the power reception control unit 292to directly calculate the position of the slot when slot information isnot received from the wireless power transmitter will be described inmore detail with reference to the accompanying drawings.

First, the power reception control unit 292 may transmit specificinformation (for example, control information (CI)) to the wirelesspower transmitter using any one of the plurality of slots. Here, thepower reception control unit 292 may receive an ACK signal from thewireless power transmitter in response to the specific information. Inthis case, the any one slot may be allocated to the power receptioncontrol unit 292. In other words, the wireless power transmitter mayallocate the any one slot to the wireless power receiver. For example,referring to FIG. 29, any one slot 2400 of a plurality of slots may beallocated to the wireless power receiver.

Subsequent to receiving the ACK signal, the power reception control unit292 may determine the position of the any one slot.

More specifically, the power reception control unit 292 may count theremaining slots located subsequent to the any one slot to determine theposition of the any one slot.

The remaining slots may be slots located subsequent to the any one slot.In other words, the remaining slots may be slots located at a distancefarther than the any one slot on the basis of a frame sync located atthe most front side of a plurality of slots constituting a frame.

For example, referring to FIG. 29, the remaining slots may be slots(slot #2, slot #3, slot #4, slot #5, slot #6, slot #7, slot #8, slot #9)located subsequent to the any one slot 2400 of a plurality of slots.

The remaining slots may be counted in various methods. For example, thepower reception control unit 292 may count the remaining slots using atleast one of i) a method of using a slot sync and ii) a method of usinga time interval of the slot.

The power reception control unit 292 may count the remaining slots onthe basis of the frame sync. More specifically, the power receptioncontrol unit 292 may count the remaining slots using a slot synctransmitted from the wireless power transmitter subsequent to thereception of the ACK signal, subsequent to a time point at which the ACKsignal is received and prior to a time point at which the frame sync isreceived.

For example, referring to FIG. 29, the power reception control unit 292may receive slot syncs 2410, 2420, 2430, 2440, 2450, 2460, 2470, 2480from the wireless power transmitter subsequent to a time point at whichthe ACK signal is received and prior to a time point at which the framesync is received. For example, the number of slot syncs 2410, 2420,2430, 2440, 2450, 2460, 2470, 2480 subsequent to a time point at whichthe ACK signal is received and prior to a time point at which the framesync is received may be 8.

In this case, the power reception control unit 292 may determine thenumber of the slot syncs as a number of the remaining slots. Forexample, when the number of slot syncs is 8, the power reception controlunit 292 may determine the number of the remaining slots as 8.

Then, the power reception control unit 292 may exclude the number of theremaining slots from the number of the plurality of slots to determinethe position of the allocated slot. For example, when the number of theplurality of slots is 9, and the number of the remaining slots is 8, thepower reception control unit 292 may determine the allocated slot as afirst slot.

Furthermore, the power reception control unit 292 may determine atransmission time point of control information to be transmitted withinthe slot using the position information of the slot. More specifically,the power reception control unit 292 may determine a transmission timepoint of control information based on a preset default value and a timeinterval of each slot. The preset default value may have a preset timeinterval as slots (for example, frame syncs and measurement slots)located at the most front side of a plurality of slots, and separatelyexisting from the plurality of slots.

For example, when the default value is 100 ms and the time interval ofeach slot is 100 ms, the power reception control unit 292 may determinea transmission time point of the control information as a time between200 ms and 300 ms.

For another example, referring to FIG. 30A, the power reception controlunit 292 may count the remaining slots using an elapsed time subsequentto a time point at which the ACK signal is received and prior to a timepoint at which the frame sync is received.

More specifically, when the ACK signal is received, the power receptioncontrol unit 292 may calculate an elapsed time subsequent to a timepoint at which the ACK signal is received and prior to a time point atwhich the frame sync is received.

Then, the power reception control unit 292 may count the remaining slotsbased on the elapsed time and time interval of each slot. For example,referring to FIG. 30A, when the elapsed time is 700 ms and the timeinterval of each slot is 100 ms, the remaining slots may be counted as7.

If a slot sync is included in the frame, then the power receptioncontrol unit 292 may count the number of the remaining slots inconsideration of a time interval of the slot sync. For example, when theelapsed time is 700 ms, and the time interval of each slot is 50 ms, andthe time interval of the slot sync is 50 ms, the remaining slots may becounted as 7. In other words, the method of counting the remaining slotsmay be applicable regardless of whether or not there exists a slot sync.

Then, the power reception control unit 292 may determine the position ofany one slot as the number of the remaining slots. For example, when thenumber of the plurality of slots is 8, the power reception control unit292 may determine the any one slot as a first positioned slot.

Furthermore, the power reception control unit 292 may determine atransmission time point of control information to be transmitted to thewireless power transmitter based on the position information of the anyone slot. Here, the power reception control unit 292 may set a timeinterval of slots (for example, frame syncs and measurement slots)provided on a frame separately from the plurality of slots to a defaultvalue to determine the control information transmission time point.

For example, when the plurality of slots has a time interval of 1000 ms,and the elapsed time is 700 ms, and the default value is 100 ms, thepower reception control unit 292 may determine a reception time point ofthe control information as a time between 200 ms and 300 ms.

On the other hand, as illustrated in FIG. 30A, when a frame providedwith a plurality of slots does not have a slot sync, the frame sync mayinclude allocation information associated with whether or not theplurality of slots are allocated. For example, the frame sync mayindicate an allocated slot as “0”, and a non-allocated slot as “1”.

In other words, as illustrated in FIG. 30B, the frame sync is in a statethat only a slot located at a first position is allocated among eightslots but the remaining slots are not allocated.

Through this, the present disclosure may reduce a collision occurrencebetween one or more wireless power receivers with respect to a wirelesspower transmitter performing communication with the one or more wirelesspower receiver.

However, it would be easily understood by those skilled in the art thatthe configuration of a wireless power transmitter according to theembodiment disclosed herein may be applicable to an apparatus, such as adocking station, a terminal cradle device, and an electronic device, andthe like, excluding a case where it is applicable to only a wirelesscharger.

The scope of the invention will not be limited to the embodimentsdisclosed herein, and thus various modifications, variations, andimprovements can be made in the present invention without departing fromthe spirit of the invention, and within the scope of the appendedclaims.

1. A communication method of a wireless power receiver performingcommunication with a wireless power transmitter, the communicationmethod comprising: transmitting control information to the wirelesspower transmitter through a slot within a frame; receiving an ACK signalfrom the wireless power transmitter, wherein the slot is allocated tothe wireless power receiver; determining a position of the allocatedslot within the frame on the basis of a sync pattern in response to thereceived ACK signal; and performing communication with the wirelesspower transmitter using the allocated slot.
 2. The communication methodof claim 1, wherein the frame comprises the sync pattern and a pluralityof slots.
 3. The communication method of claim 2, wherein the syncpattern is a wireless power signal transmitted from the wireless powertransmitter.
 4. The communication method of claim 2, wherein the syncpattern comprises a first sync pattern located at a start position ofthe frame to indicate a start of the frame and at least one second syncpattern located between two neighboring slots to indicate informationassociated with the two neighboring slots, and wherein the position ofthe allocated slot is determined by counting a number of the at leastone second sync pattern received at the wireless power receiver untilthe first sync pattern is received at the wireless power receiversubsequent to receiving the ACK signal.
 5. The communication method ofclaim 1, wherein the sync pattern is located at a start position of theframe to indicate a start of the frame, and wherein the position of theallocated slot is counted using a time interval subsequent to a timepoint at which the ACK signal is received and prior to a time point atwhich the sync pattern is received.
 6. The communication method of claim5, wherein the allocated slot has a preset time interval.
 7. Thecommunication method of claim 5, wherein the performing of thecommunication with the wireless power transmitter is to calculate a timeinterval subsequent to a time point at which the sync pattern isreceived and prior to a time point at which the allocated slot isprovided based on the position of the allocated slot.
 8. Thecommunication method of either one of claim 2, wherein the sync patterncomprises information indicating whether or not each of the plurality ofslots is allocated to a wireless power receiver.
 9. The communicationmethod of claim 1, wherein the performing of the communication with thewireless power transmitter is to transmit the control information to thewireless power transmitter only through the allocated slot based on thedetermined position.
 10. The communication method of claim 1, whereinthe performing of the communication with the wireless power transmitteris to limit the transmission of the control information to the wirelesspower transmitter through remaining slots other than the allocated slot.11. A communication method of a wireless power transmitter performingcommunication with a wireless power receiver, the communication methodcomprising: receiving control information from the wireless powerreceiver through a slot within a frame; transmitting an ACK signal tothe wireless power receiver in response to the received controlinformation; allocating the slot to the wireless power receiver toperform communication with the wireless power receiver, wherein slotinformation of the allocated slot is stored; and performingcommunication with the wireless power receiver using the allocated slot.12. The communication method of claim 11, wherein the slot informationof the allocated slot includes position information of the allocatedslot within the frame.
 13. The communication method of claim 11, whereina sync pattern is located at a start position of the frame.
 14. Thecommunication method of claim 11, wherein the control informationcomprises at least one of control error value information and poweramount information.
 15. The communication method of claim 11, whereinthe performing of the communication with the wireless power receiver isto limit the reception of the control information through the remainingslots within the frame other than the allocated slot.
 16. A wirelesspower receiver performing communication with a wireless powertransmitter, the wireless power receiver comprising: a power receptionunit configured to receive a wireless power signal from the wirelesspower transmitter; and a power reception control unit configured toperform communication with the wireless power transmitter using thewireless power signal, wherein the power reception control unit performsthe steps comprising: transmitting control information to the wirelesspower transmitter through a slot within a frame; receiving an ACK signalfrom the wireless power transmitter, wherein the slot is allocated tothe wireless power receiver; determining a position of the allocatedslot within the frame on the basis of a sync pattern in response to thereceived ACK signal; and performing communication with the wirelesspower transmitter using the allocated slot.
 17. The wireless powerreceiver of claim 16, wherein the performing of the communication withthe wireless power receiver is to receive the control information onlythrough the allocated slot within the frame.
 18. The wireless powerreceiver of claim 16, wherein the performing of the communication withthe wireless power receiver is to limit the reception of the controlinformation through the remaining slots within the frame other than theallocated slot.
 19. The wireless power receiver of claim 16, wherein theframe comprises the sync pattern and a plurality of slots.
 20. Awireless power transmitter performing communication with a wirelesspower receiver, the wireless power transmitter comprising: a powerconversion unit configured to receive a wireless power signal from thewireless power receiver; and a power transmission control unitconfigured to perform communication with the wireless power receiverusing the wireless power signal, wherein the power transmission controlunit performs the steps comprising: receiving control information fromthe wireless power receiver through a slot within a frame; transmittingan ACK signal to the wireless power receiver in response to the receivedcontrol information; allocating the slot to the wireless power receiverto perform communication with the wireless power receiver, wherein slotinformation of the allocated slot is stored; and performingcommunication with the wireless power receiver through the allocatedslot.